Journal articles on the topic 'Stretch-shortening cycle (SSC)'
To see the other types of publications on this topic, follow the link: Stretch-shortening cycle (SSC).
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the top 45 journal articles for your research on the topic 'Stretch-shortening cycle (SSC).'
Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.
You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.
Browse journal articles on a wide variety of disciplines and organise your bibliography correctly.
1
Sahrom, Sofyan B., John B. Cronin, and Nigel K. Harris. "Understanding Stretch Shortening Cycle Ability in Youth." Strength and Conditioning Journal 35, no. 3 (June 2013): 77–88. http://dx.doi.org/10.1519/ssc.0b013e318295560a.
Full text
2
Wadden, Katie P., Duane C. Button, Armin Kibele, and David G. Behm. "Neuromuscular fatigue recovery following rapid and slow stretch–shortening cycle movements." Applied Physiology, Nutrition, and Metabolism 37, no. 3 (June 2012): 437–47. http://dx.doi.org/10.1139/h2012-020.
Full textAbstract:
The purpose of this study was to investigate underlying mechanisms and neuromuscular recovery patterns following rapid and slow stretch–shortening cycle (SSC) movements performed to fatigue. Fourteen (10 moderately trained (MT) and four highly trained (HT)) subjects completed rapid and slow SSC movements to fatigue. The rapid SSC movement consisted of continuous drop jumps from a 30 cm platform until a predetermined jump height was no longer maintained, and the slow SSC movement consisted of continuous squats to 90° of knee flexion at a load of 65% of subject’s one-repetition maximum until no further repetitions could be completed. Although blood lactate measures were significantly (p < 0.002) higher after the rapid SSC condition versus after the slow SSC condition, the recovery of neuromuscular properties (maximum voluntary contractions, twitch force, muscle compound action potential) following the two conditions to fatigue did not differ. The duration of the rapid SSC movement was dependent on the training status of the subject; HT subjects performed the rapid SSC longer (68.2%) than the MT subjects until fatigued. Thus, the neuromuscular fatigue recovery patterns were independent of the type of SSC movement, condition duration, and subject training status. Because rapid and slow SSC exercises induce similar fatigue patterns, training programs incorporating rapid SSC exercises can be developed similar to that prescribed in traditional slow SSC resistance training programs.
3
Rice, Paige E., Herman van Werkhoven, Edward K. Merritt, and Jeffrey M. McBride. "Lower Leg Morphology and Stretch-Shortening Cycle Performance of Dancers." Journal of Applied Biomechanics 34, no. 3 (June 1, 2018): 211–19. http://dx.doi.org/10.1123/jab.2017-0206.
Full textAbstract:
Greater levels of bone ultimate fracture load, bone stress–strain index, muscle cross-sectional area, and maximal voluntary isometric plantarflexion (MVIP) strength of the lower leg may be adaptations from chronic exposure to stretch-shortening cycle (SSC) actions. Dancers, a population that habitually performs SSC movements primarily about the ankle joint, may serve as a novel population to gain broader understanding of SSC function. A total of 10 female collegiate dancers and 10 untrained controls underwent peripheral quantitative computed tomography scans of both lower legs and performed MVIPs, countermovement hops, and drop hops at 20, 30, and 40 cm on a custom-made inclined sled. Dancers had greater right and left ultimate fracture load values and significantly (P ≤ .05) greater left leg stress–strain index than controls. Dancers had significantly larger right and left muscle cross-sectional area and MVIP values and hopped significantly higher during all hopping conditions in comparison with controls. Average force–time and power–time curves revealed significantly greater relative force and power measurements during the concentric phase for all hopping conditions in dancers when compared with controls. This investigation provides evidence that dance may be a stimulus for positive muscle and bone adaptations, strength levels, and enhanced SSC capabilities.
4
Turner, Anthony N., and Ian Jeffreys. "The Stretch-Shortening Cycle: Proposed Mechanisms and Methods for Enhancement." Strength and Conditioning Journal 32, no. 4 (August 2010): 87–99. http://dx.doi.org/10.1519/ssc.0b013e3181e928f9.
Full text
5
Moeskops, Sylvia, Jason S. Pedley, Jon L. Oliver, and Rhodri S. Lloyd. "The Influence of Competitive Level on Stretch-Shortening Cycle Function in Young Female Gymnasts." Sports 10, no. 7 (July 6, 2022): 107. http://dx.doi.org/10.3390/sports10070107.
Full textAbstract:
This cross-sectional study investigated how stretch-shortening cycle (SSC) function and kinetic variables differed between young female gymnasts of varying competitive levels. Drop jump (DJ) force–time profiles were examined in 118 female gymnasts, sub-divided by competitive level (n = 21 recreational, n = 41 regional and n = 50 elite). DJ force–time data were analyzed to calculate performance and kinetic variables. Participants’ SSC function was categorized as poor, moderate, or good, depending on the presence of an impact peak and spring-like behavior. A high proportion of gymnasts across each group were categorized as having “good” or “moderate” SSC function (i.e., >94.8%), with a trend of increasingly better SSC function observed with competitive level. Significant differences in reactive strength index, contact time, time of landing peak force, relative propulsive peak force, impulse, and ratio of braking: propulsive impulse were found between the elite and recreational group (p < 0.05). While SSC function was generally good to moderate, elite gymnasts had a more desirable kinetic jump-landing strategy than recreational level gymnasts. Drop jump kinetic variables appear to distinguish between elite and recreational gymnasts but not between regional standard gymnasts. Practitioners should consider the kinetic profile of gymnasts when benchmarking and setting training objectives.
6
Toumi, Hechmi, Georges Poumarat, Thomas M. Best, Alain Martin, John Fairclough, and Mike Benjamin. "Fatigue and muscle–tendon stiffness after stretch–shortening cycle and isometric exercise." Applied Physiology, Nutrition, and Metabolism 31, no. 5 (October 2006): 565–72. http://dx.doi.org/10.1139/h06-034.
Full textAbstract:
The purpose of the present study was to compare vertical jump performance after 2 different fatigue protocols. In the first protocol, subjects performed consecutive sets of 10 repetitions of stretch–shortening cycle (SSC) contractions. In the second protocol, successive sets of 10 repetitions of isometric contractions were performed for 10 s with the knee at 90° of flexion. The exercises were stopped when the subjects failed to reach 50% of their maximum voluntary isometric contractions. Maximal isometric force and maximal concentric power were assessed by performing supine leg presses, squat jumps, and drop jumps. Surface EMG was used to determine changes in muscle activation before and after fatigue. In both groups, the fatigue exercises reduced voluntary isometric force, maximal concentric power, and drop jump performance. Kinematic data showed a decrease in knee muscle–tendon stiffness accompanied by a lengthened ground contact time. EMG analysis showed that the squat and drop jumps were performed similarly before and after the fatigue exercise for both groups. Although it was expected that the stiffness would decrease more after SSC than after isometric fatigue (as a result of a greater alteration of the reflex sensitivity SSC), our results showed that both protocols had a similar effect on knee muscle stiffness during jumping exercises. Both fatigue protocols induced muscle fatigue, and the decrease in jump performance was linked to a decrease in the strength and stiffness of the knee extensor muscles.
7
Perrey, Stéphane, Guillaume Millet, Robin Candau, and Jean-Denis Rouillon. "Stretch-Shortening Cycle in Roller Ski Skating: Effects of Speed." Journal of Applied Biomechanics 16, no. 3 (August 2000): 264–75. http://dx.doi.org/10.1123/jab.16.3.264.
Full textAbstract:
The purpose of this study was to examine the effects of speed on the stretch-shortening cycle (SSC) behavior during roller ski skating. Ten highly skilled male cross-country skiers roller skied at 4.56, 5.33 m · s–1and maximal speed using the V2-alternate technique on a flat terrain. Knee and ankle joint kinematics, and EMG of thevastus lateralis(VL) andgastrocnemius lateralis(GL) muscles were recorded during the last 40 s of each bout of roller skiing. Maximal speed was associated with increases in cycle rate combined with decreases in cycle length. For VL, no significant differences were observed for the integrated EMG eccentric-to-concentric ratio (iEMG Ecc/Conc) and for the stretching velocity over the range of speeds. For GL, stretching velocity and iEMG Ecc/Conc were significantly greater at maximal speed. The analysis of GL EMG activity suggests that speed improved GL stiffness so that more elastic energy was stored, a better force transmission occurred, and coupling time decreased. These findings suggest that the efficiency of roller ski skating locomotion may be increased with speed through a better use of the stretch-shortening cycle pattern in the ankle extensors.
8
Kyröläinen, Heikki, and Paavo V. Komi. "Neuromuscular function with different stretching velocities in the stretch-shortening cycle (SSC) exercises." Journal of Biomechanics 27, no. 6 (January 1994): 704. http://dx.doi.org/10.1016/0021-9290(94)91082-0.
Full text
9
Horita, T., P. Komi, I. Hämäläinen, and J. Avela. "Exhausting stretch-shortening cycle (SSC) exercise causes greater impairment in SSC performance than in pure concentric performance." European Journal of Applied Physiology 88, no. 6 (February 2003): 527–34. http://dx.doi.org/10.1007/s00421-002-0716-z.
Full text
10
Gerodimos, Vassilis, Andreas Zafeiridis, Stefanos Perkos, Konstantina Dipla, Vassiliki Manou, and Spiros Kellis. "The Contribution of Stretch-Shortening Cycle and Arm-Swing to Vertical Jumping Performance in Children, Adolescents, and Adult Basketball Players." Pediatric Exercise Science 20, no. 4 (November 2008): 379–89. http://dx.doi.org/10.1123/pes.20.4.379.
Full textAbstract:
This study examined from childhood to adulthood: (1) the effects of countermovement (use of stretch-shortening cycle-SSC) and arm-swing (AS) on vertical jumping (VJ) performance and (2) the ability to use the SSC and AS during VJ. Male basketball players (n = 106) were divided according to their age into: children (12.0 ± 0.23), young adolescents (14.5 ± 0.41), old adolescents (16.9 ± 0.27), and adults (21.9 ± 0.32). Each participant executed three maximal squat jumps (SJ), countermovement jumps without arms (CMJ) and with arms (CMJA). The contribution of SSC and AS was calculated by the augmentation (difference and percent change) in performance between CMJ and SJ, and CMJA and CMJ, respectively. CMJA performance was significantly (p < .05) higher than CMJ and SJ, and CMJ was higher than SJ within all age-groups. There were no significant differences (p > .05) among children, young and old adolescents, and adults in the percent contribution of SSC and AS to VJ performance. The variability in the contribution of SSC and AS to VJ performance was about twofold higher in children vs. adults. It appears that the ability to use the SSC and AS is not affected by the maturation process in males, trained in basketball.
11
Flanagan, Eamonn P., and Thomas M. Comyns. "The Use of Contact Time and the Reactive Strength Index to Optimize Fast Stretch-Shortening Cycle Training." Strength and Conditioning Journal 30, no. 5 (October 2008): 32–38. http://dx.doi.org/10.1519/ssc.0b013e318187e25b.
Full text
12
Malisoux, Laurent, Marc Francaux, Henri Nielens, and Daniel Theisen. "Stretch-shortening cycle exercises: an effective training paradigm to enhance power output of human single muscle fibers." Journal of Applied Physiology 100, no. 3 (March 2006): 771–79. http://dx.doi.org/10.1152/japplphysiol.01027.2005.
Full textAbstract:
Functional performance of lower limb muscles and contractile properties of chemically skinned single muscle fibers were evaluated before and after 8 wk of maximal effort stretch-shortening cycle (SSC) exercise training. Muscle biopsies were obtained from the vastus lateralis of eight men before and after the training period. Fibers were evaluated regarding their mechanical properties and subsequently classified according to their myosin heavy chain content (SDS-PAGE). After training, maximal leg extensor muscle force and vertical jump performance were improved 12% ( P < 0.01) and 13% ( P < 0.001), respectively. Single-fiber cross-sectional area increased 23% in type I ( P < 0.01), 22% in type IIa ( P < 0.001), and 30% in type IIa/IIx fibers ( P < 0.001). Peak force increased 19% in type I ( P < 0.01), 15% in type IIa ( P < 0.001), and 16% in type IIa/IIx fibers ( P < 0.001). When peak force was normalized with cross-sectional area, no changes were found for any fiber type. Maximal shortening velocity was increased 18, 29, and 22% in type I, IIa, and hybrid IIa/IIx fibers, respectively ( P < 0.001). Peak power was enhanced in all fiber types, and normalized peak power improved 9% in type IIa fibers ( P < 0.05). Fiber tension on passive stretch increased in IIa/IIx fibers only ( P < 0.05). In conclusion, short-term SSC exercise training enhanced single-fiber contraction performance via force and contraction velocity in type I, IIa, and IIa/IIx fibers. These results suggest that SSC exercises are an effective training approach to improve fiber force, contraction velocity, and therefore power.
13
Nicol, C., J. Avela, and P. V. Komi. "EFFECTS OF REPEATED EXHAUSTIVE STRETCH-SHORTENING CYCLE EXERCISE (SSC) ON SHORT LATENCY REFLEX RESPONSES 1125." Medicine & Science in Sports & Exercise 29, Supplement (May 1997): 198. http://dx.doi.org/10.1097/00005768-199705001-01123.
Full text
14
Debenham, James R., William I. Gibson, Mervyn J. Travers, Amity C. Campbell, and Garry T. Allison. "Modulation of Stretch-Shortening-Cycle Behavior With Eccentric Loading of Triceps Surae: A Possible Therapeutic Mechanism." Journal of Sport Rehabilitation 26, no. 2 (March 2017): 151–58. http://dx.doi.org/10.1123/jsr.2015-0129.
Full textAbstract:
Context:Eccentric exercises are increasingly being used to treat lower-limb musculoskeletal conditions such as Achilles tendinopathy. Despite widespread clinical application and documented efficacy, mechanisms underpinning clinical benefit remain unclear. Positive adaptations in motor performance are a potential mechanism.Objective:To investigate how an eccentric loading intervention influences measures of stretch-shortening-cycle (SSC) behavior during a hopping task.Design:Within-subjects repeated-measures observational study.Setting:University motion-analysis laboratory.Participants:Healthy adults.Interventions:A single intervention of 5 sets of 10 eccentric plantar-flexion contractions at 6 repetitions maximum using a commercial seated calf-raise machine.Main Outcome Measures:Lower-limb stiffness, sagittal-plane ankle kinematics, and temporal muscle activity of the agonist (soleus) and antagonist (tibialis anterior) muscles, measured during submaximal hopping on a custom-built sledge-jump system.Results:Eccentric loading altered ankle kinematics during submaximal hopping; peak angle shifted to a less dorsiflexed position by 2.9° and ankle angle precontact shifted by 4.4° (P < .001). Lower-limb stiffness increased from 5.9 to 6.8 N/m (P < .001), while surface EMG measures of soleus occurred 14–44% earlier (P < .001) after the loading intervention.Conclusions:These findings suggest that eccentric loading alters SSC behavior in a manner reflective of improved motor performance. Decreased ankle excursion, increased lower-limb stiffness, and alterations in motor control may represent a positive adaptive response to eccentric loading. These findings support the theory that mechanisms underpinning eccentric loading for tendinopathy may in part be due to improved “buffering” of the tendon by the neuromuscular system.
15
Elnaggar, Ragab K., Bader A. Alqahtani, Saud F. Alsubaie, Rania R. Mohamed, and Mohammed F. Elbanna. "Stretch-shortening cycle exercises can efficiently optimize gait-symmetry and balance capabilities in children with unilateral cerebral palsy: A randomized controlled trial." NeuroRehabilitation 49, no. 1 (August 14, 2021): 139–49. http://dx.doi.org/10.3233/nre-210063.
Full textAbstract:
BACKGROUND: Children with unilateral cerebral palsy (UCP) experience an asymmetrical gait pattern and poor balance capabilities. Effective interventions, therefore, are needed to facilitate remediation of these functional issues. OBJECTIVE: This study was set out to investigate the emerging role of stretch-shortening cycle (SSC) exercises on gait-symmetry and balance in children with UCP. METHODS: In this randomized controlled trial, 42 children with UCP (age; 8 –12 years) were enrolled and received either standard physical rehabilitation (control group; n = 21) or the SSC exercise program plus physical rehabilitation (SSC group; n = 21). Spatial- and temporal-gait symmetry index (GSI) and specific balance capabilities [reactive balance, directional control, movement synchronization, and sensory organization] were assessed before and after 16 sessions that were carried out twice/week over non-sequential days in an 8-week program. RESULTS: Using the pre-treatment scores as covariates, the post-treatment spatial- (P = 0.006; η p 2 = 0.17) and temporal- GSI (P < .001; η p 2 = 0.46) scores reduced significantly in the SSC group as compared to the control group, suggesting favorable improvement of gait symmetry. Also, all measures of balance (P < 0.05; η p 2 ranged between 0.10 and 0.29) improved remarkably, post-treatment, in SSC group in comparison with the control group. CONCLUSION: The evidence from this study suggests that SSC exercises besides standard physical rehabilitation appear to be effective for improving gait symmetry and boosting balance capabilities in children with UCP.
16
Kyröläinen, Heikki, Paavo V. Komi, Keijo Häkkinen, and Kim Dong Ha. "Effects of Power Training With Stretch-Shortening Cycle (SSC) Exercises of Upper Limbs in Untrained Women." Journal of Strength and Conditioning Research 12, no. 4 (November 1998): 248–52. http://dx.doi.org/10.1519/00124278-199811000-00008.
Full text
17
Kyröläinen, Heikki, Paavo V. Komi, Keijo Häkkinen, and Kim Dong Ha. "Effects of Power Training With Stretch-Shortening Cycle (SSC) Exercises of Upper Limbs in Untrained Women." Journal of Strength and Conditioning Research 12, no. 4 (1998): 248. http://dx.doi.org/10.1519/1533-4287(1998)012<0248:eoptws>2.3.co;2.
Full text
18
Fukutani, Atsuki, Jun Misaki, and Tadao Isaka. "Both the elongation of attached crossbridges and residual force enhancement contribute to joint torque enhancement by the stretch-shortening cycle." Royal Society Open Science 4, no. 2 (February 2017): 161036. http://dx.doi.org/10.1098/rsos.161036.
Full textAbstract:
This study examined the influence of the elongation of attached crossbridges and residual force enhancement on joint torque enhancement by the stretch-shortening cycle (SSC). Electrically evoked submaximal tetanic plantar flexions were adopted. Concentric contractions were evoked in the following three conditions: after 2 s isometric preactivation (ISO condition), after 1 s isometric then 1 s eccentric preactivation (ECC condition), and after 1 s eccentric then 1 s isometric preactivation (TRAN condition). Joint torque and fascicle length were measured during the concentric contraction phase. While no differences in fascicle length were observed among conditions at any time points, joint torque was significantly higher in the ECC than TRAN condition at the onset of concentric contraction. This difference would be caused by the dissipation of the elastic energy stored in the attached crossbridges induced by eccentric preactivation in TRAN condition due to 1 s transition phase. Furthermore, joint torques observed 0.3 and 0.6 s after concentric contraction were significantly larger in the ECC and TRAN conditions than in the ISO condition while no difference was observed between the ECC and TRAN conditions. Since the elastic energy stored in the attached crossbridges would have dissipated over this time frame, this result suggests that residual force enhancement induced by eccentric preactivation also contributes to joint torque enhancement by the SSC.
19
Los Arcos, Asier, and Javier Yanci. "Specificity of jumping, acceleration and quick change of direction motor abilities in soccer players." Kinesiology 49, no. 1 (2017): 22–29. http://dx.doi.org/10.26582/k.49.1.12.
Full textAbstract:
The purpose of this study was to determine the underlying structure of the stretch-shortening cycle (SSC) jumping, acceleration and change-of-direction (COD) abilities in soccer players using principal component factor analysis (PCA). Based on the results of recent studies on male college athletes, we hypothesized that slow SSC jumping, acceleration and COD represent independent motor abilities in soccer players. Forty two soccer players (23.2±2.36 yr) performed three tests for each group of rapid lower-body movements: a) three vertical slow SSC jumping tests ‒ squat jump (SJ), countermovement jump (CMJ) and arm swing countermovement jump (CMJAS), b) three acceleration tests ‒ 5, 10 and 15 meter sprint times (ACC5, ACC10 and ACC15), and c) three COD tests ‒ modified agility test free (MATF), the 505 agility test (505) and 20 yard agility test (Y20). PCA was applied to establish the relationships among the factors (i.e. motor abilities) underlying the included manifest variables (i.e. performance tests). This procedure reduced all variables to a smaller number of independent latent dimensions. The results indicated three separate factors that may correspond to slow SSC jumping, acceleration and COD abilities. The magnitude of the correlation coefficients among the three motor abilities extracted was r<.56. Therefore, it is suggested that slow SSC jumping, acceleration and COD abilities represent independent motor abilities and consequently these should be trained and evaluated separately to assess soccer players’ physical profiles.
20
Seiberl, Wolfgang, Geoffrey A. Power, Walter Herzog, and Daniel Hahn. "The stretch-shortening cycle (SSC) revisited: residual force enhancement contributes to increased performance during fast SSCs of human m. adductor pollicis." Physiological Reports 3, no. 5 (May 2015): e12401. http://dx.doi.org/10.14814/phy2.12401.
Full text
21
Tauchi, Kenji, Sungjin Yoon, and Kaoru Takamatsu. "The difference between the upper limbs and the lower limbs in individuals on force output characteristics during stretch-shortening cycle movement." Taiikugaku kenkyu (Japan Journal of Physical Education, Health and Sport Sciences) 47, no. 6 (2002): 533–46. http://dx.doi.org/10.5432/jjpehss.kj00003390738.
Full text
22
Amiri-Khorasani, Mohammadtaghi, Noor Osman, and Ashril Yusof. "Kinematics Analysis: Number of Trials Necessary to Achieve Performance Stability during Soccer Instep Kicking." Journal of Human Kinetics 23, no. 1 (January 1, 2010): 15–19. http://dx.doi.org/10.2478/v10078-010-0002-9.
Full textAbstract:
Kinematics Analysis: Number of Trials Necessary to Achieve Performance Stability during Soccer Instep KickingThe purpose of this study was to investigate the stability of kinematics responses related to stretch shortening cycle (SSC) during 10 consecutive soccer instep kicks. The kicking motions of dominant legs were captured from five experienced adult male soccer players (body height: 184.60 ± 4.49 cm; body mass: 80 ± 4.24 kg; age: 25.60 ± 1.14 years) using a three-dimensional infra-red high speed camera at 200 Hz. Some important kinematic parameters include eccentric angular velocity (AVe), concentric angular velocity (AVc), duration of eccentric (Te), and duration of concentric (Tc) at forward and impact phases selected to analyses. The AVe result of the sixth kick, relative to the first kick, was significantly lower when compared to the other kicks (with p ≤ 0.001). The AVc result of the fifth kick, relative to the first kick, was significantly lower when compared to the other kicks (with p ≤ 0.001). The Te result of the fourth kick, relative to the first kick, was significantly lower when compared to the other kicks (with p ≤ 0.011). The Tc result of the fifth kick, relative to the first kick, was significantly lower when compared to the other kicks (p ≤ 0.029). We concluded that 5 consecutive kicks are adequate to achieve high kinematic responses related to SSC.
23
Gayathri, KC. "A Comparative Study of Sports-specific Balance Training versus Plyometric Balance Training." Chettinad Health City Medical Journal 11, no. 1 (March 30, 2022): 3–8. http://dx.doi.org/10.24321/2278.2044.202202.
Full textAbstract:
Introduction: Football is a sport that involves running as the foremost part in which the lower limb plays a vital role in participation. Balance training is vital to athletic performance and should be integrated into an athlete’s daily training. Plyometric represents the performance of stretch-shortening cycle (SSC) activities that involve a high-intensity eccentric contraction straightaway after a rapid and powerful concentric contraction.Method: It is an experimental study with 30 college male football players in the age group of 18-25 years. Based on inclusion and exclusion criteria, they were divided into 2 groups. Group A consisted of 15 individuals who were trained with sports-specific balance training programmes. Group B consisted of 15 individuals who were trained with plyometric balance training. The individuals were trained for 4 weeks with 3 sessions per week (12 sessions). The pre-test and post-test measurements were measured using the triple hop test, stork balance test, and modified star excursion balance test (MSEBT).Results: Pre-test and post-test results of both groups were compared. The results showed a highly significant difference in mean values at p ≤ 0.001.Conclusion: 4 weeks of sports-specific balance training and plyometric balance training showed significant improvement in lower limb muscle strength in collegiate football players.
24
Zushi, Amane, Takuya Yoshida, Kodayu Zushi, Yasushi Kariyama, and Mitsugi Ogata. "Characteristics of three lower limb joint kinetics affecting rebound jump performance." PLOS ONE 17, no. 8 (August 15, 2022): e0268339. http://dx.doi.org/10.1371/journal.pone.0268339.
Full textAbstract:
The stretch-shortening cycle (SSC) motor execution ability of the lower limb was measured using the rebound jump index (RJ-index) in RJ test; this performance is influenced by the interaction of the forces exerted by the three joints of the lower limb.We aimed to determine RJ performance variables and identify the lower limb kinetic variables that affect them. One hundred two female university students (age, 20.1±1.0 years; height, 164.6±7.2 cm; mass, 58.9±7.3 kg) for whom RJ performance variables (RJ-index, jump height, and contact time) and joint kinetics (torque, power, and work) were measured. Statistical analysis showed a strong correlation between the RJ-index and jump height or contact time (r = 0.920, -0.726, p < 0.05) but a weak correlation between the jump height and contact time (r = -0.384, p < 0.05). Furthermore, positive ankle power was the most influential factor for RJ performance variables; additionally, positive knee power and hip work and eccentric knee torque significantly influenced jump height, and positive ankle power, negative work and power, and concentric torque significantly influenced the contact time. The acquisition of the jump height and a shorter contact time requires different kinetic variables. Furthermore, the characteristics of the force exerted by the three joints of the lower limb that compose the RJ-index may be different even if the RJ-index has the same value. Therefore, by assessing not only the RJ-index but also the jump height, contact time, and characteristics of lower limb joint kinetics in the RJ test, it is possible to conduct effective training to improve lower limb SSC motor execution performance according to individual characteristics.
25
Wan, Bingjun, Yuanyuan Gao, Ye Wang, Xiang Zhang, Hua Li, and Gongbing Shan. "Hammer Throw: A Pilot Study for a Novel Digital-Route for Diagnosing and Improving Its Throw Quality." Applied Sciences 10, no. 6 (March 11, 2020): 1922. http://dx.doi.org/10.3390/app10061922.
Full textAbstract:
The world record of the hammer throw has not been broken since 1986. This stagnation is multifactorial. One dominant factor could be the lack of evidence-based scientific/biofeedback training. This study aims to identify key parameters influencing throw quality and structure a new digital method for biofeedback training. Wire-tension measurement and 3D motion capture technology (VICON 12-camera system) were applied in quantifying and comparing throws of a national-level and a college-level athlete. Our results reveal that multi-joint coordination influences heavily on wire-tension generation. Four phases, i.e., initiation, transition, turns, and throw, play various roles in evaluating the quality of a throw. Among them, the transition, the third turn, and the throw display explosive/rapid increases of tension. For improving the effectiveness of the skill, the whip-like control and proper SSC (stretch-shortening cycle) of muscle groups involved should be established through years of training. Furthermore, our study unveils that quick and complex full-body control could be quantified and characterized by four key parameters: wire-tension, hand- and hip-height, and trunk tilt. Hence, a wearable digital device with tension and three Inertial Measurement Unit (IMU) sensors would have great potential in realizing real-time biomechanical feedback training in practice for evaluating and improving the efficiency of various training programs.
26
Arabatzi, Fotini, Theodoros M. Kannas, Gerasimos Tzilios, Georgios Stefanis, Ioanna Stefani, and Evanggelia Savva. "Differences in Vertical Performance Caused by Drop Jumping on Surfaces with Different Stiffness." Journal of Advances in Sports and Physical Education 5, no. 3 (March 18, 2022): 43–51. http://dx.doi.org/10.36348/jaspe.2022.v05i03.002.
Full textAbstract:
It is well established that muscle activation regulates leg stiffness to optimize stretch shortening cycle (SSC) performance. There is a significant interaction between the surface properties, muscle activation and leg stiffness. The aim of this study was to examine the potentiating adjustments after drop jumps (DJs) executed on two surfaces with different elasticity. Twenty-two adults randomly performed 3 protocols: Protocols with three pre-conditioning DJs performed on a springboard (PSB), Protocol (PG) with three pre-conditioning DJs performed on a stiff ground surface and Protocol without any type of pre-conditioning (C). Vertical jump performance was evaluated at four time points: before (COND0), immediately after pre-conditioning (COND10), and after 1 (COND60) and 2 min (COND120) of rest. Dynamics, kinematics and electromyographic parameters of the ankle were evaluated. ANOVA with repeated measures revealed statistically significant increase in Hpeak, Ppeak and Kleg was observed (p<0.05), over split-intervals and rest periods for Protocol (PSB) while no differences were recorded in jump kinematics. Both protocols (PSB and PG) significantly decreased CI during the pre-activation and eccentric phase, whereas the CI was increased during the concentric phase. The positive effect observed in jump performance could not be attributed to co-activity of the ankle joint, indicating that jumping on an elastic surface, may be beneficial in cases where increased leg stiffness is a determining factor for final performance.
27
Gross, Micah, Jan Seiler, Bastien Grédy, and Fabian Lüthy. "Kinematic and Kinetic Characteristics of Repetitive Countermovement Jumps with Accentuated Eccentric Loading." Sports 10, no. 5 (May 6, 2022): 74. http://dx.doi.org/10.3390/sports10050074.
Full textAbstract:
Two methods for challenging the musculoskeletal and nervous systems to better exploit the stretch-shortening cycle (SSC) mechanism during plyometric training are reactive strength exercises and accentuated eccentric loading (AEL). Combining repetitive, reactive jumping with AEL poses a novel approach, in which the effects of both methods may be combined to elicit a unique stimulus. This study compared kinematic, kinetic, and electromyographic variables between a control (CON1) and two AEL conditions (AEL2 and AEL3). Additionally, non-reactive and reactive jumps performed within these sets were compared. Participants performed two sets of six countermovement jumps (CMJ) under each loading condition. AEL3 had moderate to large positive effects (es) on peak and mean eccentric force (es = 1.1, 0.8, respectively; both p < 0.01), and eccentric loading rate (es = 0.8, p < 0.01), but no effect on concentric variables or muscle activation intensity. The effects of AEL2 were similar but smaller. With or without AEL, there were moderate to large positive effects associated with reactive CMJ (second jump in a set, compared to the first) on peak and mean eccentric velocity (es = 1.7, 0.8, respectively; both p < 0.01), peak and mean eccentric force (es = 1.3, 1.2, p < 0.01), eccentric loading rate (es = 1.3, p < 0.01) and muscle activity (es = 1.8–1.9, p < 0.01). Concentric variables did not differ. Thus, the flight phase and act of landing during reactive jumps elicited greater increases in eccentric forces, loading rates, and muscle activity than AEL. Nonetheless, kinetic variables were greatest when AEL was combined with reactive jumping. Considering the limitations or complexity associated with most AEL protocols, sets of repetitive (reactive) CMJ may be more pragmatic for augmenting eccentric kinetic variables and neuromuscular stimuli during training.
28
Ettema, G. J., P. A. Huijing, G. J. van Ingen Schenau, and A. de Haan. "Effects of prestretch at the onset of stimulation on mechanical work output of rat medial gastrocnemius muscle-tendon complex." Journal of Experimental Biology 152, no. 1 (September 1, 1990): 333–51. http://dx.doi.org/10.1242/jeb.152.1.333.
Full textAbstract:
Work output of rat gastrocnemius medialis (GM) muscle (N = 5) was measured for stretch-shortening contractions, in which initiation of stretch occurred prior to the onset of activation, and for contractions with an isometric prephase. Duration of the active prephase (prestretch and pre-isometric) varied from 20 to 200 ms. Subsequent shortening (from optimum length + 4 mm to optimum length −2mm) lasted 150 ms. Stretch velocities of 5, 10 and 20 mm s-1 were used, and the shortening velocity was 40 mm s-1. The effects of several combinations of active stretch duration and active stretch amplitude were compared. Using force-compliance characteristics, the work of the contractile element (CE), elastic energy storage and release of the undamped series elastic component (SEC) were distinguished. During shortening, an extra amount of work output was produced, induced by active stretch, of which the largest contribution (70–80%) was due to higher elastic energy release. Enhancement of the storage and utilization of elastic energy during the stretch-shortening cycle, caused by higher transition-point forces (i.e. force at onset of shortening), increased with active stretch amplitude and was associated with a net loss of work, probably due to cross-bridge detachment during active stretch. Net work over the stretch-shortening cycle remained positive for all prestretch contractions, indicating that when a muscle performs this type of contraction, it is able to contribute to work performance on body segments. It is concluded that, in stretch-shortening movements of rat GM muscle, maximal positive work output is incompatible with maximal net work output. Consequences for complex movements in vivo are discussed.
29
Baker, Brent A., Robert R. Mercer, Ken B. Geronilla, Michael L. Kashon, G. R. Miller, and Robert G. Cutlip. "Stereological analysis of muscle morphology following exposure to repetitive stretch-shortening cycles in a rat model." Applied Physiology, Nutrition, and Metabolism 31, no. 2 (April 1, 2006): 167–79. http://dx.doi.org/10.1139/h05-009.
Full textAbstract:
Repetitive motion is one risk factor associated with contraction-induced muscle injury, which leads to skeletal muscle degeneration, inflammation, and dysfunction. Since current methods are unable to quantify the acute degenerative and inflammatory responses of muscle tissue concurrently, the purpose of this study was to quantify the temporal myofiber response after exposure to injurious stretch-shortening cycles (SSCs) using a standardized stereological technique. Functional testing was performed on the ankle dorsiflexor muscles of Sprague-Dawley rats in vivo. Rats were anesthetized and exposed to 15 sets of 10 SSCs. Control rats were exposed to 15 sets of single isometric contractions of the same stimulation duration. Changes in muscle morphometry were assessed at 0.5, 24, 48, 72, and 240 h post-exposure to quantify the degree of myofiber degeneration and inflammation in the tibialis anterior muscle from each group. There was an increase in the volume density and average thickness of degenerating myofibers over time in the muscle collected from rats exposed to SSCs (p < 0.0001) that was significantly greater than in muscle exposed to isometric contractions at 24, 48, and 72 h post-exposure (p = 0.003). The volume density of degenerative myofibers was associated with functional deficits at 48 h. Stereological quantification of degenerative myofibers and interstitial space changes were associated with functional defects 48-72 h after SSC-induced injury, thus demonstrating stereology is an accurate measure of SSC-induced skeletal muscle injury.Key words: stereology, morphometry, myofiber degeneration, interstitial space, stretch-shortening cycles.
30
Cutlip, Robert G., Brent A. Baker, Ken B. Geronilla, Michael L. Kashon, and John Z. Wu. "The influence of velocity of stretch–shortening contractions on muscle performance during chronic exposure: age effects." Applied Physiology, Nutrition, and Metabolism 32, no. 3 (March 2007): 443–53. http://dx.doi.org/10.1139/h07-014.
Full textAbstract:
Aging increases injury susceptibility and impairs the ability to adapt to repetitive exposures of mechanical loading. The objective of this research was to investigate if movement velocity affects muscle response to a chronic administration of stretch–shortening cycles (SSCs) differently in young vs. old rats. Dorsiflexor muscles of old (30 months, n = 5) and young rats (12 weeks, n = 6) were exposed 3 times/week for 4.5 weeks to a protocol of 80 maximal SSCs per exposure in vivo. Skeletal muscle response was characterized by high- (500°/s) and low- (60°/s) velocity dynamic performance, which was evaluated using peak eccentric force, isometric pre-stretch force, eccentric force enhancement above the isometric pre-stretch force, negative work, and positive work. The performance of the young and old groups was not statistically different at the start of the exposure. By the end of the exposure, however, a statistical difference was noted—performance increased significantly in the young animals and decreased significantly in the old animals. The SSC velocity had a profound effect on muscle response. The young animals’ high- and low-velocity performances increased during the chronic exposure period, whereas the old animals’ performances declined. High-velocity performance increased more than low-velocity performance in young animals. In contrast, old animals suffered the most loss in high-velocity performance over the chronic exposure period. A chronic exposure of SSCs results in a significant performance increase in young animals, and a significant performance decrease in old animals. These differences are more profound during high-velocity movements. These findings suggest that age may impair the ability of skeletal muscle to adapt to repetitive mechanical loading, particularly during high-velocity movements.
31
Groeber, Martin, Savvas Stafilidis, and Arnold Baca. "The effect of stretch–shortening magnitude and muscle–tendon unit length on performance enhancement in a stretch–shortening cycle." Scientific Reports 11, no. 1 (July 16, 2021). http://dx.doi.org/10.1038/s41598-021-94046-2.
Full textAbstract:
AbstractStretch-induced residual force enhancement (rFE) is associated with increased performance in a stretch–shortening cycle (SSC). Although the influence of different range of motions and muscle–tendon unit lengths has been investigated in pure stretch-hold experiments in vivo, the contribution to a SSC movement in human muscles remains unclear. In two sessions, 25 healthy participants performed isometric reference (ISO), shortening hold (SHO) and SSC contractions on an isokinetic dynamometer. We measured the net knee-joint torque, rotational mechanical work, knee kinematics and fascicle behavior (m. vastus lateralis) of the upper right leg. In session 1 the SHO- and SSC-magnitude was changed respectively (SHO: 50°–20°, 80°–20° and 110°–20°; SSC: 20°–50°–20°, 20°–80°–20° and 20°–110°–20°) and in session 2 the muscle–tendon unit length (SHO: 50°–20°, 80°–50° and 110°–80°; SSC: 20°–50°–20°, 50°–80°–50° and 80°–110°–80°; straight leg = 0°). In both sessions, rotational work was significantly (p < 0.05) increased in the SSC compared to the SHO contractions (in the range of 8.1–17.9%). No significant difference of joint torque was found in the steady-state for all SSC-magnitudes compared to the corresponding SHO contractions in session 1. In session 2, we found only significantly (p < 0.05) less depressed joint torque in the SSC at the longest muscle–tendon unit length compared to the corresponding SHO condition, without any differences in knee kinematics and fascicle behavior. Therefore, the physiological relevance of rFE might be particularly important for movements at greater muscle–tendon unit lengths.
32
Tomalka, André, Sven Weidner, Daniel Hahn, Wolfgang Seiberl, and Tobias Siebert. "Power Amplification Increases With Contraction Velocity During Stretch-Shortening Cycles of Skinned Muscle Fibers." Frontiers in Physiology 12 (March 31, 2021). http://dx.doi.org/10.3389/fphys.2021.644981.
Full textAbstract:
Muscle force, work, and power output during concentric contractions (active muscle shortening) are increased immediately following an eccentric contraction (active muscle lengthening). This increase in performance is known as the stretch-shortening cycle (SSC)-effect. Recent findings demonstrate that the SSC-effect is present in the sarcomere itself. More recently, it has been suggested that cross-bridge (XB) kinetics and non-cross-bridge (non-XB) structures (e.g., titin and nebulin) contribute to the SSC-effect. As XBs and non-XB structures are characterized by a velocity dependence, we investigated the impact of stretch-shortening velocity on the SSC-effect. Accordingly, we performedin vitroisovelocity ramp experiments with varying ramp velocities (30, 60, and 85% of maximum contraction velocity for both stretch and shortening) and constant stretch-shortening magnitudes (17% of the optimum sarcomere length) using single skinned fibers of rat soleus muscles. The different contributions of XB and non-XB structures to force production were identified using the XB-inhibitor Blebbistatin. We show that (i) the SSC-effect is velocity-dependent—since the power output increases with increasing SSC-velocity. (ii) The energy recovery (ratio of elastic energy storage and release in the SSC) is higher in the Blebbistatin condition compared with the control condition. The stored and released energy in the Blebbistatin condition can be explained by the viscoelastic properties of the non-XB structure titin. Consequently, our experimental findings suggest that the energy stored in titin during the eccentric phase contributes to the SSC-effect in a velocity-dependent manner.
33
Fukutani, Atsuki, and Tadao Isaka. "Influence of muscle length on the stretch-shortening cycle in skinned rabbit soleus." Scientific Reports 9, no. 1 (December 2019). http://dx.doi.org/10.1038/s41598-019-54959-5.
Full textAbstract:
AbstractMuscle force generated during shortening is instantaneously increased after active stretch. This phenomenon is called as stretch-shortening cycle (SSC) effect. It has been suggested that residual force enhancement contributes to the SSC effect. If so, the magnitude of SSC effect should be larger in the longer muscle length condition, because the residual force enhancement is prominent in the long muscle length condition. This hypothesis was examined by performing the SSC in the short and long muscle length conditions. Skinned fibers obtained from rabbit soleus (N = 20) were used in this study. To calculate the magnitude of SSC effect, the SSC trial (isometric-eccentric-concentric-isometric) and the control trial (isometric-concentric-isometric) were conducted in the short (within the range of 2.4 to 2.7 μm) and long muscle (within the range of 3.0 to 3.3 μm). The magnitude of SSC effect was calculated as the relative increase in the mechanical work attained during the shortening phase between control and SSC trials. As a result, the magnitude of SSC effect was significantly larger in the long (176.8 ± 18.1%) than in the short muscle length condition (157.4 ± 8.5%) (p < 0.001). This result supports our hypothesis that the magnitude of SSC effect is larger in the longer muscle length condition, possibly due to the larger magnitude of residual force enhancement.
34
Fukutani, Atsuki, Tadao Isaka, and Walter Herzog. "Evidence for Muscle Cell-Based Mechanisms of Enhanced Performance in Stretch-Shortening Cycle in Skeletal Muscle." Frontiers in Physiology 11 (January 8, 2021). http://dx.doi.org/10.3389/fphys.2020.609553.
Full textAbstract:
Force attained during concentric contraction (active shortening) is transiently enhanced following eccentric contraction (active stretch) in skeletal muscle. This phenomenon is called stretch-shortening cycle (SSC) effect. Since many human movements contain combinations of eccentric and concentric contractions, a better understanding of the mechanisms underlying the SSC effect would be useful for improving physical performance, optimizing human movement efficiency, and providing an understanding of fundamental mechanism of muscle force control. Currently, the most common mechanisms proposed for the SSC effect are (i) stretch-reflex activation and (ii) storage of energy in tendons. However, abundant SSC effects have been observed in single fiber preparations where stretch-reflex activation is eliminated and storage of energy in tendons is minimal at best. Therefore, it seems prudent to hypothesize that factor(s) other than stretch-reflex activation and energy storage in tendons contribute to the SSC effect. In this brief review, we focus on possible candidate mechanisms for the SSC effect, that is, pre-activation, cross-bridge kinetics, and residual force enhancement (RFE) obtained in experimental preparations that exclude/control the influence of stretch-reflex activation and energy storage in tendons. Recent evidence supports the contribution of these factors to the mechanism of SSCs, and suggests that the extent of their contribution varies depending on the contractile conditions. Evidence for and against alternative mechanisms are introduced and discussed, and unresolved problems are mentioned for inspiring future studies in this field of research.
35
Fukutani, Atsuki, Tadao Isaka, and Walter Herzog. "Evidence for Muscle Cell-Based Mechanisms of Enhanced Performance in Stretch-Shortening Cycle in Skeletal Muscle." Frontiers in Physiology 11 (January 8, 2021). http://dx.doi.org/10.3389/fphys.2020.609553.
Full textAbstract:
Force attained during concentric contraction (active shortening) is transiently enhanced following eccentric contraction (active stretch) in skeletal muscle. This phenomenon is called stretch-shortening cycle (SSC) effect. Since many human movements contain combinations of eccentric and concentric contractions, a better understanding of the mechanisms underlying the SSC effect would be useful for improving physical performance, optimizing human movement efficiency, and providing an understanding of fundamental mechanism of muscle force control. Currently, the most common mechanisms proposed for the SSC effect are (i) stretch-reflex activation and (ii) storage of energy in tendons. However, abundant SSC effects have been observed in single fiber preparations where stretch-reflex activation is eliminated and storage of energy in tendons is minimal at best. Therefore, it seems prudent to hypothesize that factor(s) other than stretch-reflex activation and energy storage in tendons contribute to the SSC effect. In this brief review, we focus on possible candidate mechanisms for the SSC effect, that is, pre-activation, cross-bridge kinetics, and residual force enhancement (RFE) obtained in experimental preparations that exclude/control the influence of stretch-reflex activation and energy storage in tendons. Recent evidence supports the contribution of these factors to the mechanism of SSCs, and suggests that the extent of their contribution varies depending on the contractile conditions. Evidence for and against alternative mechanisms are introduced and discussed, and unresolved problems are mentioned for inspiring future studies in this field of research.
36
Joumaa, Venus, Atsuki Fukutani, and Walter Herzog. "Energy Cost of Force Production After a Stretch-Shortening Cycle in Skinned Muscle Fibers: Does Muscle Efficiency Increase?" Frontiers in Physiology 11 (January 18, 2021). http://dx.doi.org/10.3389/fphys.2020.567538.
Full textAbstract:
Muscle force is enhanced during shortening when shortening is preceded by an active stretch. This phenomenon is known as the stretch-shortening cycle (SSC) effect. For some stretch-shortening conditions this increase in force during shortening is maintained following SSCs when compared to the force following a pure shortening contraction. It has been suggested that the residual force enhancement property of muscles, which comes into play during the stretch phase of SSCs may contribute to the force increase after SSCs. Knowing that residual force enhancement is associated with a substantial reduction in metabolic energy per unit of force, it seems reasonable to assume that the metabolic energy cost per unit of force is also reduced following a SSC. The purpose of this study was to determine the energy cost per unit of force at steady-state following SSCs and compare it to the corresponding energy cost following pure shortening contractions of identical speed and magnitude. We hypothesized that the energy cost per unit of muscle force is reduced following SSCs compared to the pure shortening contractions. For the SSC tests, rabbit psoas fibers (n = 12) were set at an average sarcomere length (SL) of 2.4 μm, activated, actively stretched to a SL of 3.2 μm, and shortened to a SL of 2.6 or 3.0 μm. For the pure shortening contractions, the same fibers were activated at a SL of 3.2 μm and actively shortened to a SL of 2.6 or 3.0 μm. The amount of ATP consumed was measured over a 40 s steady-state total isometric force following either the SSCs or the pure active shortening contractions. Fiber stiffness was determined in an additional set of 12 fibers, at steady-state for both experimental conditions. Total force, ATP consumption, and stiffness were greater following SSCs compared to the pure shortening contractions, but ATP consumption per unit of force was the same between conditions. These results suggest that the increase in total force observed following SSCs was achieved with an increase in the proportion of attached cross-bridges and titin stiffness. We conclude that muscle efficiency is not enhanced at steady-state following SSCs.
37
Dantas, Matheus, Victor Sabino de Queiros, Fabiano de Souza Fonseca, Paulo Francisco de Almeida-Neto, Rômulo Vasconcelos Teixeira, Leandro Medeiros da Silva, Felipe J. Aidar, Dihogo Gama de Matos, and Breno Guilherme de Araújo Tinoco Cabral. "The stretch-shortening cycle efficiency is dependent on the maturational stage." Revista Brasileira de Cineantropometria & Desempenho Humano 22 (2020). http://dx.doi.org/10.1590/1980-0037.2020v22e72597.
Full textAbstract:
Abstract Maturation interferes with physiological and mechanical aspects of muscle contraction. The aim of the present study was to compare the efficiency of the stretch-shortening cycle (SSC) between different maturation stages. One hundred forty six young people, with 72 boys and 74 girls, were recruited to participate in the study. Sexual maturation was measured and the group was stratified into adolescents (> 3 auto-tanner) and children (<2 auto-tanner). Squat jump (SJ) and countermovement jump (CMJ) performance were measured to measure reactive force (RF) capacity, eccentric utilization ratio (EUR) and pre-stretch augmentation (PSAP). The children did not present statistical difference between SJ and CMJ (t(55)= -1.93; ∆ = -0.61; 95% CI = -1.24 to -0.02; p = 0.058), while the adolescents presented higher performance of CMJ (t(89)= -12.28; ∆ = -2.44; 95% CI = -2.84 to -2.05; p <0.001). In addition, adolescents had higher RF performance (t(144)= 5.18; p <0.0001; 95% CI = 2.53 to 1.13), PSAP (t(144)= 4.38; p <0.0001; 95% CI = 14.00 to 5.29) and EUR (t(144)= 4.38; p <0.0001; 95% CI = 0.14 to 0.05). We conclude that more mature young people have better SSC utilization.
38
Holmberg, Patrick M., Peter W. Harrison, David G. Jenkins, and Vincent G. Kelly. "Factors Modulating the Priming Response to Resistance and Stretch-Shortening Cycle Exercise Stimuli." Strength & Conditioning Journal Publish Ahead of Print (May 31, 2022). http://dx.doi.org/10.1519/ssc.0000000000000728.
Full text
39
Ojeda-Aravena, Alex, Tomás Herrera-Valenzuela, Pablo Valdés-Badilla, Eduardo Baez-San Martín, José Zapata-Bastías, Esteban Aedo-Muñoz, and José Manuel García-García. "Interrelationship between specific high-intensity intermittent efforts ability with aerobic capacity and slow stretch-shortening cycle utilization in taekwondo athletes." Isokinetics and Exercise Science, November 26, 2021, 1–10. http://dx.doi.org/10.3233/ies-210210.
Full textAbstract:
BACKGROUND: Repeat high-intensity intermittent efforts is a taekwondo-specific ability but the influence of aerobic capacity and dynamic strength characteristics on this ability has received relatively little attention in the literature. OBJECTIVE: To examine the relationship between specific high-intensity intermittent efforts with aerobic capacity and slow stretch-shortening cycle utilization in taekwondo athletes. METHODS: Nineteen taekwondo male athletes were assessed by squat jump (SJ), countermovement jump (CMJ), 20-meter shuttle run (20MSR), and frequency speed of kick test multiple (FSKTMULT). From the FSKTMULT, total kicks and kick decrement index [KDI] were calculated. Additionally, from both jump tests, the slow stretch-shortening cycle utilization (Slow SSC Utilization) was determined from the eccentric utilization ratio [EUR], pre-stretch augmentation [PSA], and reactive strength index [RSI]. RESULTS: There were positive and significant correlations between total kicks with 20MSR (r= 0.85; p= 0.00) and SJ (r= 0.66; p< 0.05). The multiple regression model demonstrated that total kicks where significantly influenced by 20MSR (R2= 71%; p= 0.00). Additionally, only EUR and RSI explained total kicks performance to a greater proportion (R2= 76%). CONCLUSIONS: The FSKTMULT total kicks performance is positively correlated and influenced by aerobic capacity and slow SSC utilization.
40
Held, Steffen, Tobias Siebert, and Lars Donath. "Electromyographic activity of the vastus medialis and gastrocnemius implicates a slow stretch-shortening cycle during rowing in the field." Scientific Reports 10, no. 1 (June 11, 2020). http://dx.doi.org/10.1038/s41598-020-66124-4.
Full textAbstract:
Abstract The consideration of the temporal and electromyographic (EMG) characteristics of stretch-shortening cycles (SSC) are crucial for the conceptualization of discipline-specific testing and training. Since leg muscles are first stretched (eccentric) and then contracted (concentric) during rowing, it can be assumed that the entire muscle tendon complex performs a SSC. Thus, it should be elucidated whether the rowing cycle can be attributed to either a slow or fast SSC. Therefore, EMG of the vastus medialis and gastrocnemius were captured (n = 10, 22.8 ± 3.1 years, 190 ± 6 cm, 82.1 ± 9.8 kg) during (single scull) rowing and subsequently compared to typical slow (countermovement jump, CMJ) and fast (drop jump, DJ) SSCs. The elapsed time between the EMG onset and the start of the eccentric phase was monitored. The pre-activation phase (PRE, before the start of the eccentric phase) and the reflex-induced activation phase (RIA 30–120 ms after the start of the eccentric phase) have been classified. Notable muscular activity was observed during DJ before the start of the eccentric phase (PRE) as well as during RIA. In contrast, neither CMJ nor rowing revealed any EMG-activity in these two phases. Interestingly, CMJ and race-specific rowing showed an EMG-onset during the eccentric phase. We conclude that rowing is more attributable to a slow SSC and implies that fast SSC does not reflect discipline specific muscle action and could hamper rowing-performance-enhancement.
41
Monti, Elena, Janice Waldvogel, Ramona Ritzmann, Kathrin Freyler, Kirsten Albracht, Michael Helm, Niccolò De Cesare, et al. "Muscle in Variable Gravity: “I Do Not Know Where I Am, But I Know What to Do”." Frontiers in Physiology 12 (August 4, 2021). http://dx.doi.org/10.3389/fphys.2021.714655.
Full textAbstract:
Purpose: Fascicle and sarcomere lengths are important predictors of muscle mechanical performance. However, their regulation during stretch-shortening cycle (SSC) activities in usual and challenging conditions is poorly understood. In this study, we aimed to investigate muscle fascicle and sarcomere behavior during drop jumps (a common SSC activity) in conditions of variable gravity.Methods: Fifteen volunteers performed repeated drop jumps in 1 g, hypo-gravity (0 to 1 g), and hyper-gravity (1 to 2 g) during a parabolic flight. Gastrocnemius medialis (GM) electromyographic activity and fascicle length (Lf) were measured at drop-off, ground contact (GC), minimum ankle joint angle (MAJ), and push-off. GM sarcomere number was estimated by dividing Lf, measured by ultrasound at rest, by published data on GM sarcomere length, and measured in vivo at the same joint angle. Changes in sarcomere length were estimated by dividing GM Lf in each jump phase by sarcomere number calculated individually. The sarcomere force-generating capacity in each jump phase was estimated from the sarcomere length-tension relationship previously reported in the literature.Results: The results showed that, regardless of the gravity level, GM sarcomeres operated in the ascending portion of their length-tension relationship in all the jump phases. Interestingly, although in hypo-gravity and hyper-gravity during the braking phase (GC-MAJ) GM fascicles and sarcomeres experienced a stretch (as opposed to the quasi-isometric behavior in 1 g), at MAJ they reached similar lengths as in 1 g, allowing sarcomeres to develop about the 70% of their maximum force.Conclusion: The observed fascicle behavior during drop jumping seems useful for anchoring the tendon, enabling storage of elastic energy and its release in the subsequent push-off phase for effectively re-bouncing in all gravity levels, suggesting that an innate neuromuscular wisdom enables to perform SSC movements also in challenging conditions.
42
Rosa, Hyago Bernardes da, Vinícius da Silva Lessa de Oliveira, Lucas Souza Santos, Samuel Klippel Prusch, Igor Martins Barbosa, and Luiz Fernando Cuozzo Lemos. "O uso do ciclo alongamento-encurtamento em saltos de atletas de handebol e praticantes de musculação do sexo feminino." Revista de Educação Física / Journal of Physical Education 85, no. 3 (September 29, 2016). http://dx.doi.org/10.37310/ref.v85i3.176.
Full textAbstract:
Introdução: O handebol é caracterizado como um esporte de cunho coletivo, possuindo grande variedade de movimentações e seus ganhos propiciam melhoramentos nas qualidades físicas e funcionais. Por outro lado, a musculação, que é amplamente praticada atualmente, possibilita muitos ganhos, porém, proporciona baixo melhoramento funcional. O Ciclo Alongamento-Encurtamento (CAE) está baseado no fato de o músculo realizar ativamente uma ação, sendo parte dessa energia armazenada nos componentes elásticos e reutilizada na próxima ação muscular.Objetivo: Comparar a utilização do CAE na potência dos membros inferiores entre os grupos analisados.Métodos: A amostra foi constituída por 16 atletas de handebol (GH) e 12 praticantes de musculação (GM), ambos do sexo feminino. Foi mensurada a potência através da plataforma de contato e atividade eletromiográfica dos músculos: bíceps femoral, reto femoral, gastrocnêmio medial e vasto lateral, através de testes de saltos verticais: Squat Jump e Counter Movement Jump.Resultados: As diferenças estatísticas significativas encontradas entre os grupos foram: o tempo de prática para o GH foi maior, o tempo de prática semanal para o GM foi superior e o percentual de utilização do CAE que para o GH foi de -2,63 e no GM foi de 13,32, para o músculo vasto lateral.Conclusão: Por meio dos resultados obtidos por testes de saltos verticais, o GH utilizou com maior eficiência a força elástica, apresentando superioridade na economia de ativação do vasto lateral. Portanto, as praticantes de musculação são menos econômicas, possivelmente por seu treinamento isolado.Use Stretch-Shortening Cycle in Leaps Handball Athletes and Female BodybuildersIntroduction: Handball is a sport of collective nature, featuring a great variety of moves and its gains provide improvements in physical and functional qualities. However, bodybuilding, which is commonly practiced nowadays, allows many gains, nonetheless, provides low functional improvement. The Stretch-Shortening Cycle (SSC) is based on the fact that the muscle acts actively, with a part of this energy stored in the elastic components and reutilized on the next muscular action.Methods: The sample was built by 16 handball athletes (GH) and 12 bodybuilding practitioners (GM), both of the womankinds. The potency was measured through the muscular contact and electromyographic activity platform: Biceps femoris, rectus femoris, medial gastrocnemius and vastus lateralis, with vertical jumps: Squat Jump e Counter Movement Jump.Objective: To compare the use of the SSC on the potency of the inferior limbs amongst the analyzed groups.Results: The significant statistical differences found between the group were: the practice time for the GH was higher, the weekly practice time for the GM was higher and the usage percentage of the SSC for the GH was of -2.63 and in the GM was of 13.32, for the vastus lateralis muscle.Conclusion: With the results obtained with tests of vertical jumps, the GH used the elastic force more efficiently, displaying superiority on the activation economy of the vastus lateralis. Therefore, the bodybuilding practitioners are less economic, possibly due to their isolated training.
43
Costa, Filipe E., Rafael L. Kons, Fabio Y. Nakamura, and Juliano Dal Pupo. "Acute and prolonged effects of the simulated physical demands of a futsal match on lower limb muscle power and strength, sprint performance and muscle soreness." Isokinetics and Exercise Science, September 29, 2021, 1–9. http://dx.doi.org/10.3233/ies-210153.
Full textAbstract:
BACKGROUND: Prolonged fatigue effects may be a concern after futsal matches mainly because of the actions performed by futsal players (e.g., sprinting, jumping) that usually involve the stretch-shortening cycle (SSC). However, there no studies analyzed the prolonged effects of futsal-specific fatigue and how futsal players can recover from performance tasks. OBJECTIVE: To analyze the acute and prolonged effects of a protocol that simulates specific physical demands of futsal on countermovement-jump, sprint performance, muscle strength and muscle soreness. METHODS: Fifteen amateur futsal male athletes (18.3 ± 3.8 years) performed a futsal intermittent running protocol (FIRP) and were assessed for (moment production, sprint and jumping performance and muscle soreness) at pre, during half-time, immediately after, post 24 and 48 hours after the FIRP. Analysis of variance (repeated measures) was used to compare variable means over time. RESULTS: The main results indicated a decrement in the CMJ height (p= 0.03) and an increase of 10 m and 20 m sprint times (p= 0.01–p< 0.01, respectively) during half-time and the post FIRP. There was a decrement in eccentric peak moment of the knee extensors (p= 0.02) and flexors (p< 0.01) until 48h post protocol and a decrement in concentric peak moment of the flexors (p< 0.01) post protocol. Athletes reported muscle soreness in the hamstrings (p= 0.03) post and 24 h after the FIRP. CONCLUSION: FIRP induced acute effects in the jump and sprint performances only. On the other hand, the knee moment production capability (mainly eccentric) suffered acute and also prolonged effects of the FIRP accompanied by delayed muscle soreness in the hamstring muscles.
44
Corea, Cleiton Silva, and Ronei Silveira Pinto. "EFEITOS DE DIFERENTES TIPOS DE TREINAMENTO DE FORÇA NO DESEMPENHO DE CAPACIDADES FUNCIONAIS EM MULHERES IDOSAS." Estudos Interdisciplinares sobre o Envelhecimento 16, no. 1 (January 4, 2011). http://dx.doi.org/10.22456/2316-2171.13300.
Full textAbstract:
Os diferentes tipos de treinamento de força (TF) apresentam distintas adaptações do tecido muscular como o desenvolvimento de força máxima, potência e/ou força reativa muscular. Dentre estes tipos de TF, estão os treinamentos de força tradicional (TFT), potência (TP) e de força reativa, em que está presente o ciclo-alongamento-encurtamento (CAE) (TR). A habilidade de produzir força rapidamente requer a participação intensa das fibras do tipo IIX, condição esta frequentemente reduzida em mulheres idosas. A força rápida tem importância significativa, para homens e mulheres de todas as idades, destacando-se ainda mais em mulheres idosas. A prescrição de um tipo de TF que melhor desenvolva as atividades de vida diária (AVD) é primordial para a manutenção da independência física e qualidade de vida de idosas. A metodologia embasou-se em pesquisa bibliográfica, utilizando artigos atuais e clássicos da literatura sobre TF em mulheres idosas (publicados a partir de 2000) selecionados nas bases de dados Pubmed e Sportdiscus, que comparassem e analisassem pelo menos dois tipos específicos de TF (TFT, TP e TR). Sendo assim, o objetivo do presente estudo de revisão foi comparar os efeitos de três diferentes tipos de TF no desempenho de capacidades funcionais em mulheres idosas. Como resultados os artigos consultados apresentam um consenso de que o TP e TR desenvolvam de forma mais eficaz as capacidades funcionais de mulheres idosas e que o TR é mais efetivo no desenvolvimento da força reativa muscular que o TP. Dessa forma, conclui-se que o TR é mais efetivo para o desenvolvimento da produção de força rápida do músculo que os outros tipos específicos de treinamento de força e por consequência disto, melhor desenvolve as capacidades funcionais de mulheres idosas. EFFECTS OF DIFFERENT TYPES OF STRENGTHTRAINING ON THE FUNCTIONAL CAPACITY PERFORMANCE IN ELDERLY WOMEN abstract Distinct adaptations of muscle tissue as the development of maximum strength, power and/or reactive muscle strength seems to be associated with different programs of strength training (ST). Among these several programs, there are the traditional strength training (TST), the power training (PT) and the reactive force, in which is present the stretch-shortening cycle (SSC) (RT). The ability to produce force rapidly requires intense participation of the type IIX fibers. This condition is often reduced in older women. However, this kind of force adaptation is very important for the elderly women functional capacity. Consequently, the prescription of one type of ST that best carries out the activities of daily living (ADL) is essential for maintaining physical independence and quality of life of elderly women. Therefore, the aim of this review study was to compare the effects of three different programs of ST in the performance of functional abilities in older women throughout a research on the current and classic papers (published since 2000) selected from the Pubmed and SPORTDiscus databases, that compare and analyze at least two specific types of ST (i.e. TST, PT and RT). The results of our review showed that the PT and RT are more effective for the development of functional capacities for older women than the other programs studied. Furthermore, the RT is more effective in developing reactive muscular strength exercises with the use of SSC than PT. The conclusion of the present study was that RT is more effective than the others specific programs studied of strength training for the development of rapid force. as well as, it was the best program associated with the development of the functional capacity for older women.
45
Buonocunto, M., A. Lyon, T. Delhaas, J. Heijman, and J. Lumens. "Understanding the contribution of stretch-activated ion channels to cardiac arrhythmogenesis using computational modelling." EP Europace 24, Supplement_1 (May 18, 2022). http://dx.doi.org/10.1093/europace/euac053.610.
Full textAbstract:
Abstract Funding Acknowledgements Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Dutch heart foundation, ERA-CVD Introduction Cardiac electrophysiology and mechanics are strongly interconnected. Among other things, their interaction is mediated by cardiac mechano-electric feedback through stretch-activated ion-channels (SACs). These channels are also thought to contribute to the development of arrhythmias, but their precise role remains unclear. Purpose To elucidate the contribution of SACs to arrhythmias using a novel computational model of cardiac electromechanics. Methods We implemented two types of SACs in the O’Hara-Rudy model (ORd) of human ventricular electrophysiology: potassium-selective SACs and non-selective SACs (conducting sodium and potassium). The model was calibrated based on experimental human and rodent data of cardiomyocytes undergoing stretch. The calibration also considered inter-species differences, age, and upregulation of SACs under disease conditions. Subsequently, we varied the amplitude, duration, and timing of the simulated stretch to investigate their effects on action potential (AP). Results The model reproduced APs measured experimentally. Early afterdepolarizations, delayed afterdepolarizations, and ectopic beats were observed when applying stretch with short duration (e.g. 20ms) and high amplitude (e.g. 40%). When varying the time of application, stretch applied closer to the subsequent beat (cycle length: 1000ms) also shortened the following AP duration (APD) (shortening of 30ms with stretch at t=600ms, 130ms at t=800ms). Higher sensitivity to stretch was observed when simulating disease-related remodelling of SACs. Milder effects (no APD shortening with stretch at t=600ms and t=800ms) were seen with a lower stretch amplitude (e.g. 10% with SACs disease-related remodelling, 15% without). Failure of repolarization only occurred when sustained stretch (1000ms duration) of more than 10% (with SACs disease-related remodelling) or 15% (without) was applied. Conclusions Using a novel human electromechanical computational model, we quantified the contribution of SACs to cardiac AP changes. We showed that both disease-related SAC remodelling and variations of amplitude, timing, and duration of cardiomyocyte stretch modulated the effects on cardiac electrophysiology. We also showed that SACs may lead to afterdepolarizations and shorten the subsequent AP duration, factors which may potentially contribute to the generation of arrhythmias.