scholarly journals Greater volumes are required to reduce muscle performance in well-trained individuals

Author(s):  
Filipe Dinato de Lima ◽  
Amilton Vieira ◽  
Ana Luiza Matias Correia ◽  
Ricardo Moreno Lima ◽  
Andrew Correa da Fonseca ◽  
...  

A specific drop jumps (DJs) protocol (using 100 jumps) has been largely used to induce muscle damage. However, it failed to show relevant drop in performance in well-trained individuals. Trained subjects may require a protocol with greater volume to induce decrease of muscle performance. The aim of this study was to assess muscle performance after two DJs damaging protocols with different volumes in well-trained individuals. Eighteen strength and/or power-trained males (4.92 ± 2.78 years of training experience) were randomly assigned into one of two groups: DJ100 (five sets of 20 DJs) or DJ140 (seven sets of 20 DJs), with 2-min of rest interval. DJs were performed from a 60-cm box. After landing, the volunteers performed a maximal vertical rebound jump. Muscle swelling increased significantly on both DJ100 and DJ140 (p < 0.001). Maximal isometric torque (MIT) decreased significantly on both DJ100 (p = 0.005) and DJ140 (p < 0.001). MIT showed no between-group difference on pre-assessment (p = 0.815). However, on post-assessment, MIT was significantly lower on DJ140 than DJ100 (p = 0.043). Countermovement jump (CMJ) decreased significantly on DJ140 (p = 0.001), but not on DJ100 (p = 0.802). There was no between-group difference on pre-assessment (p = 0.978). However, on post-assessment, CMJ was significantly lower on DJ140 than DJ100 (p = 0.038). DJ140 induced greater drop in isometric strength than DJ100 and only DJ140 significantly reduced jump performance. These results demonstrated that well-trained individuals require a great volume of DJs to reduce substantially muscle performance.

2020 ◽  
Vol 32 (2) ◽  
pp. 81-88 ◽  
Author(s):  
K. Katsikari ◽  
Eleni Bassa ◽  
Dimitrios Skoufas ◽  
Savvas Lazaridis ◽  
Christos Kotzamanidis ◽  
...  

Purpose: To examine the effect of a 10-week plyometric training (PT) on the kinematic and kinetic properties of prepubescent girls during squat jump, countermovement jump, and drop jumps. Methods: Twenty-four untrained girls (aged 9–11 y) were assigned to a training group (TG) and a control group. The TG followed twice a week PT for 10 weeks. Squat jump, countermovement jump, and drop jumps performed from heights of 20, 35, and 50 cm were tested before and after PT. Jump height, kinematic, and kinetic parameters were evaluated using a motion analysis system and a force plate. Results: Jumping height in all jump types increased significantly after PT for the TG (P < .001). After training, the TG presented increased power (P < .001) and knee angular velocity (P < .001), higher knee flexion at the deepest point during the braking phase (P < .001), longer contact time (P < .001), and unchanged stiffness and reaction strength index (P > .05). No differences were observed in the control group (P > .05). Conclusion: These findings indicate that a 10-week PT positively affected jumping performance in prepubescent girls who improved their drop jump performance after training not by adopting a stiff/bouncing jumping style of short contact time and increased stiffness, but a compliant/absorbing style of prolonged contact time.


2020 ◽  
pp. 1-8
Author(s):  
Mahfoodha Al Kitani ◽  
Ahmed Ambussaidi ◽  
Majid Al Busafi ◽  
Badriya Al-Hadabi ◽  
Radhouane Haj Sassi ◽  
...  

BACKGROUND: The use of post-activation potentiation (PAP) exercises at the end of the warm-up may increase muscles nerve conduction speed and per consequent improve speed, strength and explosive power performances. OBJECTIVE: To assess the effect of PAP during warm-up using vertical or horizontal drop jumps on repeated sprints performance combined with countermovement jump in young handball players. METHODS: 12 young handball players participated in this study. Participants realized 3 randomized warm-up protocols: a warm-up without PAP, a warm-up with PAP using vertical drop jumps, and a warm-up with PAP using horizontal drop jumps. After the assigned PAP protocol, the subject realized a counter movement jump as a reference value (CMJr), and thereafter repeated sprint tests with and without changing of direction (six maximal 2 × 12.5 m shuttle sprints and six maximal 25 m straight sprints, respectively) combined with vertical jumping. RESULTS: Horizontal drop jump during warm-up showed larger improvements in repeated sprints performance with and without change of direction for the parameters best time and mean time, compared with warm up without drop jumps (p< 0.01) and warm up with vertical drop jumps (p< 0.05). Vertical drop jump performance during warm-up induced greater gains in countermovement jump reference value in comparison with warm up without drop jump (p< 0.01), or warm up with horizontal drop jump (p< 0.01). CONCLUSION: PAP during warm-up using horizontal drop jump improves repeated sprints performance with and without changing of direction while PAP using vertical drop jump improves CMJ reference value.


2018 ◽  
Vol 13 (7) ◽  
pp. 953-956 ◽  
Author(s):  
Michely V. Andreatta ◽  
Victor M. Curty ◽  
João Victor S. Coutinho ◽  
Miguel Ângelo A. Santos ◽  
Paula F. Vassallo ◽  
...  

Purpose: To evaluate whether cell-free DNA (cfDNA) levels increase immediately after an acute light and heavy resistance exercise (RE) bout and whether cfDNA levels are associated with functional muscle capacity up to 48 h after an exercise session. Methods: Twenty healthy volunteers performed 3 sets of leg-press RE with 80% of 1-repetition maximum (1RM) (RE80) or 40% of 1RM (RE40) with similar exercise volume. Blood lactate was measured after completion of the 3 sets. Creatine kinase, cfDNA, and jump performance were evaluated before (pre) exercise, immediately postexercise (post-0h), and every 24 h until 48 h. Results: Lactate concentration increased similarly in both groups (RE40 4.0 [1.3] mmol/L; RE80 4.8 [1.3] mmol/L). No changes were observed in squat-jump and countermovement-jump performance after RE40; however, both jumps remained reduced until 48 h in the RE80 group. Creatine kinase concentration increased post-24h only in the RE80 group (pre 128.8 [73.7] U/L to post-24h 313.8 [116.4] U/L). cfDNA concentration increased post-0h only in the RE80 group (pre 249.8 [82.3] ng/mL to post-0h 406.3 [67.2] ng/mL). There was a negative correlation between post-0h cfDNA concentration and post-24h squat jump (r = −.521; P = .01) and post-0h cfDNA concentration and post-24h countermovement jump (r = −.539; P = .01). Conclusion: cfDNA increases in response to RE intensity even when not performed until exhaustion. cfDNA measured immediately after RE is a promising biomarker for muscle-performance decrement up to 48 h after a RE bout.


1997 ◽  
Vol 22 (2) ◽  
pp. 117-132 ◽  
Author(s):  
Andrew D. Walshe ◽  
Gregory J. Wilson

This study investigated the relationship between musculotendinous stiffness and the ability to perform dynamic stretch-shorten cycle actions involving a range of eccentric loads. Twenty trained male subjects performed a series of quasi-static muscular actions in a supine leg press position, during which a brief perturbation was applied. The resulting damped oscillations allowed the estimation of each subject's maximal musculotendinous stiffness (k) for the lower body musculature. All subjects also performed a countermovement jump (CMJ) and a series of drop jumps (DJs) from heights of 20, 40, 60, 80, and 100 cm. When the jump heights of the nine most compliant (mean k = 11.4 ± 2.7 kN•m−1) and nine stiffest (mean k = 20.5 ± 2.5 kN•m−1) subjects were compared, the stiff subjects demonstrated significantly poorer capacity to perform under the highest (DJ80 and DJ100) eccentric loading conditions. It was hypothesised that the relatively greater forces transmitted from the skeletal system to the musculature of the stiff subjects reduced their ability to attenuate the higher eccentric loads due to less effective contractile dynamics and greater levels of reflex induced inhibition. Key words: series elastic component, compliance, drop jump, muscle elasticity, eccentric contraction


2019 ◽  
Vol 69 (1) ◽  
pp. 239-247 ◽  
Author(s):  
Ronaldo Kobal ◽  
Lucas A. Pereira ◽  
Katia Kitamura ◽  
Anderson C. Paulo ◽  
Henrique A. Ramos ◽  
...  

Abstract The aim of this study was to compare the acute effects of performing half squats (HSs) with different loading intensities (1, 3, and 5 repetitions maximum [RM], and 60% 1RM) and a different number of sets (1, 2, and 3) on the countermovement jump (CMJ) performance of 18 highly‐trained male subjects. Participants were submitted to four experimental conditions (1RM, 3RM, 5RM, and 60% 1RM) in randomized order. The CMJ was assessed before and after each set. Differences in CMJ performance between the distinct experimental conditions and individual responses in CMJ performance induced by the different protocols were analyzed via the magnitude‐based inference method. Overall, significant improvements were detected in individual CMJ heights after each activation protocol. It can be concluded that the use of 1 to 3 sets of HSs performed at moderate‐to‐high loads may be an effective strategy to improve jump performance in highly‐trained subjects. Nonetheless, despite the high efficiency of the protocols tested here, coaches and researchers are strongly encouraged to perform individualized assessments within the proposed range of loads and sets, to find optimal and tailored post‐activation potentiation protocols.


Author(s):  
Vitor Hugo Santos Rezende ◽  
Diego de Alcântara Borba ◽  
Lucas Augusto de Souza ◽  
Suene Franciele Nunes Chaves ◽  
Maria Hipólito Almeida Pinheiro ◽  
...  

Abstract This study aimed to evaluate the effects of cumulative school soccer matches separated by 24-h or 48-h intervals on the recovery status of U-19 players. Thirty-four school athletes (17.6 ± 1.1 years) who played in an U-19 school soccer competition (composed of one group with four teams and another group with three teams, followed by semifinals and final) were examined before three matches, which lasted 70 min. Seventeen athletes had a 24-h rest interval between each match (GGG group), while 18 athletes had a 48-h rest interval between the second and third matches (GG48hG group). Total Quality Recovery, countermovement jump, 10-m sprint, and maximum lumbar isometric strength were measured. The internal load of each match was calculated by the product of the session Rating of Perceived Exertion and match time. There was a 22% reduction in Total Quality Recovery (p< 0.001) and 12% in 10-m sprint performance (p< 0.001) before the third match in the GGG group, while the GG48hG group showed no changes for the same variables (p> 0.05). The countermovement jump decreased before the second match in both groups (GGG= 12% and GG48hG= 10%; p< 0.001), with no difference between groups (p> 0.05). In addition, both groups showed no changes in the isometric strength or the internal load match over the games (p> 0.05). Despite not providing complete muscle recovery, a 48-h interval between the second and third matches seems to have minimized the reduction of muscle performance due to consecutive matches.


2021 ◽  
Vol 2 (2021) ◽  
pp. 17-27
Author(s):  
Sebastian Möck ◽  
◽  
René Hartmann ◽  
Klaus Wirth ◽  
◽  
...  

A high level of sprinting performance is relevant in various sports. Because of the transition of movement patterns in different sprint sections there is a shift in the relevance of speed-strength of the knee and hip extensors, and stretch-shortening cycle performance seems conceivable. Fifty-six physical education students (23.70 ± 3.00 years, 176.9 ± 8.10cm, 74.20 ± 10.30kg) were investigated. They performed sprints up to 30m in which different sections were analyzed and vertical jumps (squat jump, countermovement jump, drop jump from different dropping heights). Vertical jumping tests in squat jump and countermovement jump revealed mean values of 31.95 ± 6.56cm and 34.28 ± 7.47cm, respectively, while the drop jumps showed mean RSI values between 155.11 ± 36.77 and 168.24 ± 36.29 dependent on the dropping height. The sprint test showed a mean performance of 4.464 ± .343s (30m). The correlational analysis showed significant correlations (p < .01) for vertical jumping height with all sprinting sections (r = −.652 to −.834). Drop jump performance also showed significant correlations (p < .01) with all the sections (r = −.379 to −.594). The results let us hypothesize that the observed sample generated similar ground-reaction forces in the sprint and drop jump from a height of 40 cm.


2019 ◽  
Vol 66 (1) ◽  
pp. 195-203 ◽  
Author(s):  
Ronaldo Kobal ◽  
Lucas A. Pereira ◽  
Katia Kitamura ◽  
Anderson C. Paulo ◽  
Henrique A. Ramos ◽  
...  

Abstract The aim of this study was to compare the acute effects of performing half squats (HSs) with different loading intensities (1, 3, and 5 repetitions maximum [RM], and 60% 1RM) and a different number of sets (1, 2, and 3) on the countermovement jump (CMJ) performance of 18 highly-trained male subjects. Participants were submitted to four experimental conditions (1RM, 3RM, 5RM, and 60% 1RM) in randomized order. The CMJ was assessed before and after each set. Differences in CMJ performance between the distinct experimental conditions and individual responses in CMJ performance induced by the different protocols were analyzed via the magnitude-based inference method. Overall, significant improvements were detected in individual CMJ heights after each activation protocol. It can be concluded that the use of 1 to 3 sets of HSs performed at moderate-to-high loads may be an effective strategy to improve jump performance in highly-trained subjects. Nevertheless, despite the high efficiency of the protocols tested here, coaches and researchers are strongly encouraged to perform individualized assessments within the proposed range of loads and sets, to find optimal and tailored post-activation potentiation protocols.


Author(s):  
José María González-Ravé ◽  
Anthony P. Turner ◽  
Shaun M. Phillips

Swimming training programs may help to limit declines in cardiovascular conditioning, muscle strength, mobility and social functioning in individuals with Down’s Syndrome (DS): (1) Background: This study aims to analyze the effects of a periodized swimming training program on swimming speed, lower body force and power and body composition in a group of swimmers with DS; (2) Methods: Nine swimmers with DS (2 men and 7 women; aged 21–30 years-old) completed an 18-week periodized swimming program. The swimmers were assessed, pre and post-training, for 25 m, 50 m and 100 m freestyle swim performance, countermovement jump performance and body composition; (3) Results: Significant and large improvements in 25 m (mean −6.39%, p < 0.05, d = 1.51), 50 m (mean −4.95%, p < 0.01, d = 2.08) and 100 m (mean −3.08%, p < 0.05, d = 1.44) freestyle performance were observed following training, with no significant changes in body composition or consistent changes in jump performance (although a large mean 14.6% decrease in relative peak force, p < 0.05, d = 1.23) (4) Conclusions: A periodized 18-week training intervention may improve swimming performance in a small group of trained swimmers with DS, with less clear changes in jump performance or body composition. This program provides a training profile for coaches working with swimmers with DS and a platform for further research into the benefits of swimming training with this under-represented population.


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