Effects on Performance of Variable Eccentric Loads during Depth Jumps

1995 ◽  
Vol 4 (1) ◽  
pp. 31-41 ◽  
Author(s):  
James C. Radcliffe ◽  
Louis R. Osternig
Keyword(s):  
Body Weight ◽  
Small Proportion ◽  
Small Amplitude ◽  
Vertical Jump ◽  
Considerable Variability ◽  
Large Depth ◽  
Jumping Performance ◽  
Squat Exercise ◽  
Healing Tissue ◽  
Extreme Care

Seventy subjects were tested for (a) percent body weight controlled (lowered and raised) by the lower extremities via parallel squat exercise, (b) maximum vertical jump-reach, and (c) maximal depth jump-reach from six heights ranging from 0.30 to 1.05 m. The results suggest that maximum parallel squat performance represents a small proportion (8%) of the variance contributing to controlling increasing depth jump heights and that specific improvement in jumping performance may be achieved by relatively small amplitude prestretch movements rather than large depth jump heights. The implications of the present findings for the use of depth jumping in conditioning and rehabilitative protocols are that (a) extreme care must be exercised in selecting jump heights, as there is considerable variability in individual tolerance to a given height, and (b) depth jumping should be contraindicated in cases where high impulse loads can disrupt healing tissue and, if it is used in postinjury situations, should be reserved for the end phase of rehabilitation.

scholarly journals Postactivation potentiation improves jumps performance in children ages 6 to 8 years old

2021 ◽  
Vol 38 (3) ◽  
pp. 192-196
Author(s):  
C Gerber ◽  
P Sirieiro ◽  
I Nasser ◽  
C Taber ◽  
H Miranda
Keyword(s):  
Body Mass ◽  
Vertical Jump ◽  
Cross Sectional Study ◽  
Postactivation Potentiation ◽  
Cross Sectional ◽  
Jump Performance ◽  
Jumping Performance ◽  
Jump Test ◽  
Low Load ◽  
Vertical Jumps

Introduction: The aim of the present study was to investigate the effects of postactivation potentiation (PAP) in vertical and horizontal jump performance in pre-pubertal children. Material and method: One hundred and nineteen children (65 girls and 54 boys; 6.8 ± 0.7 years old; 124.5 ± 6.4 cm; 25.2 ± 5.1 kg) participated in this study. This was a transversal cross-sectional study which incorporated a within-subjects repeatedmeasures design, where participants completed all protocols. The experimental procedure required four total testing, separated by one week, using a counterbalanced. This study investigated jumping performance associated with weighted jumps, lowload vertical jumps, and horizontal jumps. During two sessions the participants performed vertical jumps with and without PAP, the other two sessions the same procedures were performed for horizontal jumps. The PAP protocol consisted of one set of five weighted countermovement jumps with low-load (10% of body mass) and a rest interval of four minutes prior to the jump tests. Paired t-tests were used between conditions (PAP and control) in the vertical jump and horizontal jump test. In addition, Cohen’s d effect size and 95% confidence interval was used. Results: Significant jump height was observed in the vertical jump in the PAP condition compared to the control condition (p = 0.007). Similar results were observed for the horizontal jump tests, with significant longer distance observed in the PAP condition (p = 0.036). Conclusions: Pre-pubertal children can benefit from the effects of PAP in vertical and horizontal jumping performance when preceded by low-load ballistic movements. A protocol implementing low-loads, determined by a relative percentage of body mass is effective to promote PAP for young children.

scholarly journals Neuromuscular Control of the Knee during a Resisted Single-Limb Squat Exercise

2005 ◽  
Vol 33 (10) ◽  
pp. 1520-1526 ◽  
Author(s):  
Richard K. Shields ◽  
Sangeetha Madhavan ◽  
Emy Gregg ◽  
Jennifer Leitch ◽  
Ben Petersen ◽  
...  
Keyword(s):  
Body Weight ◽  
Knee Joint ◽  
Knee Flexion ◽  
Neuromuscular Control ◽  
Biceps Femoris ◽  
Medial Gastrocnemius ◽  
Isometric Contractions ◽  
Low Resistance ◽  
Squat Exercise ◽  
Flexion And Extension

Background Closed kinetic chain exercises such as single-limb squats are preferred for knee rehabilitation. A complete understanding of the neuromuscular control of the knee during the single-limb squat is essential to increase the efficiency of rehabilitation programs. Hypothesis Performing a controlled single-limb squat with resistance to knee flexion and extension will increase the coactivation of the hamstring muscle group, thus reducing the quadriceps/hamstrings ratio. Study Design Descriptive laboratory study. Methods A total of 15 healthy human subjects (7 women, 8 men) performed controlled single-limb squats in a custom mechanical device that provided resistance to both flexion and extension. Subjects performed the task at 3 levels of resistance, set as a percentage of body weight. Surface electromyographic recordings from 7 muscles (gluteus medius, rectus femoris, vastus medialis oblique, vastus lateralis, biceps femoris, semitendinosus, and medial gastrocnemius) were collected during the task. Results Biceps femoris activity during knee flexion increased from approximately 12% maximum voluntary isometric contractions during low resistance (0% body weight) to approximately 27% maximum voluntary isometric contractions during high resistance (8% body weight). Although the quadriceps had greater activity than the hamstrings at all levels of resistance, the quadriceps/hamstrings ratio declined significantly with resistance (F2,27 = 29.05; P=. 012) from 3.0 at low resistance to 2.32 at the highest resistance. Conclusions Performing controlled resisted single-limb squats may help to simultaneously strengthen the quadriceps and facilitate coactivation of the hamstrings, thus reducing anterior tibial shear forces. The coactivation may also increase the dynamic control of the knee joint. Clinical Relevance The typical single-limb squat exercise performed in the clinic does not usually control for bidirectional resistance and knee joint excursion. As seen in this study, controlled single-limb squats at increased levels of resistance help to increase the coactivation of the hamstring muscles, which is essential to optimize neuromuscular control of the knee.

scholarly journals Can We Rely on Flight Time to Measure Jumping Performance or Neuromuscular Fatigue-Overload in Professional Female Soccer Players?

2020 ◽  
Vol 10 (13) ◽  
pp. 4424
Author(s):  
Estrella Armada-Cortés ◽  
Javier Peláez Barrajón ◽  
José Antonio Benítez-Muñoz ◽  
Enrique Navarro ◽  
Alejandro F. San Juan
Keyword(s):  
Gold Standard ◽  
Vertical Jump ◽  
Intraclass Correlation ◽  
Smartphone Application ◽  
Flight Time ◽  
Neuromuscular Fatigue ◽  
Football Players ◽  
Validity And Reliability ◽  
Jumping Performance ◽  
Significant Difference

The main purpose of this study was to compare the validity of the take-off velocity method (TOV) measured with a force platform (FP) (gold standard) versus the flight time method (FT) in a vertical jump to measure jumping performance or neuromuscular fatigue-overload in professional female football players. For this purpose, we used a FP and a validated smartphone application (APP). A total of eight healthy professional female football players (aged 27.25 ± 6.48 years) participated in this study. All performed three valid trials of a countermovement jump and squat jump and were measured at the same time with the APP and the FP. The results show that there is a lack of validity and reliability between jump height (JH) calculated through the TOV method with the FP and the FT method with the FP (r = 0.028, p > 0.84, intraclass correlation coefficient (ICC) = −0.026) and between the JH measured with the FP through the TOV method and the APP with the FT method (r = 0.116, p > 0.43, ICC = −0.094 (−0.314–0.157)). A significant difference between the JH measured through the TOV with the FP versus the APP (p < 0.05), and a trend between the JH obtained with the FP through the TOV and the FT (p = 0.052) is also shown. Finally, the JH with the FP through the FT and the APP did not differ (p > 0.05). The eta-squared of the one-way ANOVA was η2 = 0.085. It seems that only the TOV measured with a FP could guarantee the accuracy of the jump test in SJ+CMJ and SJ, so it is recommended that high-level sportswomen and men should be assessed with the FP through TOV as gold standard technology to ensure correct performance and/or fatigue-overload control during the sport season.

The influence of resistance bands on frontal plane knee mechanics during body-weight squat and vertical jump movements

2012 ◽  
Vol 11 (3) ◽  
pp. 438-439
Author(s):  
Chad E. Gooyers ◽  
Tyson A.C. Beach ◽  
David M. Frost ◽  
Jack P. Callaghan
Keyword(s):  
Body Weight ◽  
Vertical Jump ◽  
Frontal Plane ◽  
Knee Mechanics ◽  
Resistance Bands

The influence of resistance bands on frontal plane knee mechanics during body-weight squat and vertical jump movements

2012 ◽  
Vol 11 (3) ◽  
pp. 391-401 ◽  
Author(s):  
Chad E. Gooyers ◽  
Tyson A.C. Beach ◽  
David M. Frost ◽  
Jack P. Callaghan
Keyword(s):  
Body Weight ◽  
Vertical Jump ◽  
Frontal Plane ◽  
Knee Mechanics ◽  
Resistance Bands

scholarly journals The Effects of Successive Soccer Matches on the Internal Match Load, Stress Tolerance, Salivary Cortisol and Jumping Performance in Youth Soccer Players

2021 ◽  
Vol 80 (1) ◽  
pp. 173-184
Author(s):  
Julio Cesar Barbosa de Lima Pinto ◽  
Romerito Sóstenes Canuto de Oliveira ◽  
Nicole Leite Galvão-Coelho ◽  
Raissa Nóbrega de Almeida ◽  
Alexandre Moreira ◽  
...  
Keyword(s):  
Stress Tolerance ◽  
Salivary Cortisol ◽  
Repeated Measures ◽  
Vertical Jump ◽  
Soccer Players ◽  
Enzyme Linked Immunosorbent Assay ◽  
Jump Height ◽  
Youth Soccer ◽  
Jumping Performance ◽  
Vertical Jump Height

Abstract The study aim was to analyze the effects of successive matches on the internal match load, stress tolerance, salivary cortisol concentration and countermovement vertical jump height in twelve youth soccer players (16.6 ± 0.5 yr; 175 ± 8 cm; 65 ± 8 kg) who performed four official matches within a four day-period with a 24-h recovery interval between the matches. The internal match load, monotony index and competitive strain, as well as stress tolerance were examined. Saliva samples were collected and countermovement vertical jump height was assessed 60 min pre and 30 min post each match; delta of salivary cortisol and countermovement vertical jump height for each match were analyzed. Salivary cortisol was analyzed using an enzyme-linked immunosorbent assay. The results of ANOVA with repeated measures showed no differences between matches for the internal match load (p > 0.05). The scores of the monotony index and competitive strain were 4.3 (±2.3) and 8104 (±6795) arbitrary units, respectively. There was no difference for stress tolerance between matches (p > 0.05). Delta values of salivary cortisol were not different among the assessed matches (F(3,33) = 1.397, p = 0.351, η2: 0.09); however, delta of countermovement vertical jump height decreased from match 1 to match 4 (F(3,33) = 8.64, p < 0.001, η2: 0.44). The current findings suggest that participating in four successive matches, with 24-h of recovery in between, may not lead to changes in stress tolerance and salivary cortisol of youth players, but it may induce a decrease in players’ jumping performance after the fourth match.

scholarly journals Acute fatigue effects on ground reaction force of lower limbs during countermovement jumps

2013 ◽  
Vol 19 (4) ◽  
pp. 737-745
Author(s):  
Carlos Gabriel Fábrica ◽  
Paula V. González ◽  
Jefferson Fagundes Loss
Keyword(s):  
Body Weight ◽  
Ground Reaction Force ◽  
Reaction Force ◽  
The Body ◽  
Lower Limbs ◽  
Vertical Ground Reaction Force ◽  
External Work ◽  
Jumping Performance ◽  
Vertical Ground ◽  
The Relationship

Parameters associated with the performance of countermovement jumps were identified from vertical ground reaction force recordings during fatigue and resting conditions. Fourteen variables were defined, dividing the vertical ground reaction force into negative and positive external working times and times in which the vertical ground reaction force values were lower and higher than the participant's body weight. We attempted to explain parameter variations by considering the relationship between the set of contractile and elastic components of the lower limbs. We determined that jumping performance is based on impulsion optimization and not on instantaneous ground reaction force value: the time in which the ground reaction force was lower than the body weight, and negative external work time was lower under fatigue. The results suggest that, during fatigue, there is less contribution from elastic energy and from overall active state. However, the participation of contractile elements could partially compensate for the worsening of jumping performance.

scholarly journals The effects of 8-week core training on the development of some motoric features among 18 year-old footballers18 yaş grubu futbolcularda 8 haftalik merkez bölge (core) antrenmanlarının bazı motorik özelliklerin gelişimine etkisi

2016 ◽  
Vol 13 (3) ◽  
pp. 4595 ◽  
Author(s):  
Yakup Akif Afyon ◽  
Abdurrahman Boyacı
Keyword(s):  
Body Weight ◽  
Test Scores ◽  
Vertical Jump ◽  
T Test ◽  
Control Group ◽  
Strength Development ◽  
Football Clubs ◽  
Post Test ◽  
Core Training ◽  
Training Control

The purpose of the present research is investigating the effects of core trainings on some motoric features (strength and speed) among 18 year-old footballers. In the present research, 20 experiment group (age =18 years, body weight =71,66±6,61 kg, height =171,75±5,86 cm) and 20 control group (age =18 years, body weight =70,66±5,74 kg, height =171,75±2,99 cm), the total of 40 certified footballers, who played in 2013-2014 season, participated in the present research.Before the trainings, pre-test scores (sit-up, push-up, plank, vertical jump, medicine ball throwing, 30 m speed) were recorded. 30-35 minute core trainings, 2 days a week, for 8 weeks were conducted on the control group in addition to their regular training. Control group participants followed their regular yearly training program. At the end of the trainings, post-test scores of both groups were recorded by two experts in the field in accordance with the protocol. In order to evaluate the effects of 8-week core trainings of the strength development of footballers, paired t test was utilized for in-group comparisons and independent samples t test was utilized for inter-group comparisons.Consequently, it was observed that 8-week core training in addition to football trainings contributed to the strength and speed development among footballers. Accordingly, core trainings can be advised for football trainers, who work for youth teams of football clubs. ÖzetBu araştırmanın amacı 18 yaş grubu futbolcularda bölgesel (core) antrenmanların bazı motorik özelliklerin (kuvvet ve sürat) gelişimine etkisinin incelenmesidir. Araştırmaya 2013-2014 sezonunda lisanslı olarak futbol oynayan 20 denek grubundan (yaş =18 yıl, vücut ağırlığı =71,66±6,61 kg, boy =171,75±5,86 cm) ve 20 kontrol grubundan (yaş =18 yıl, vücut ağırlığı =70,66±5,74 kg, boy =171,75±2,99 cm) olmak üzere 40 futbolcu katıldı.Antrenmanlar öncesi grupların ön testleri (mekik, şınav, plank, dikey sıçrama, sağlık topu fırlatma, 30 m. sürat) alındı. Deney grubuna normal antrenmanlarına ek olarak 8 hafta boyunca haftada 2 kez günde 30-35 dk. core antrenmanlar uygulandı. Kontrol grubuna ise yıllık antrenman programında yer alan olağan antrenmanlar uygulandı. Antrenmanlar sonunda grupların son test ölçümleri alanında uzman iki kişi tarafından protokole uygun bir şekilde alındı. 8 hafta boyunca uygulanan merkez bölge (core) antrenmanlarının futbolcuların kuvvet gelişimine etkisinin değerlendirilmesinde grup içi karşılaştırmalarda paired t testinden gruplar arası karşılaştırmalarda independent sample t testinden yararlanılmıştır.Sonuç olarak; futbol antrenmanlarına ek olarak uygulanacak 8 haftalık merkez bölge (core) antrenmanlarının futbolcuların kuvvet ve sürat gelişimine katkı sağladığı görüldü. Bu nedenle bölgesel (core) antrenman alt yapılarda çalışan futbol antrenörlerine önerilebilir.

scholarly journals The acute effects of a dynamic warm-up including hip mobility exercises on sprint, agility and vertical jump performance

2020 ◽  
Vol 45 ◽  
pp. 55-61
Author(s):  
Onat Cetin ◽  
Ozkan Isik
Keyword(s):  
Body Weight ◽  
Vertical Jump ◽  
Collegiate Athletes ◽  
Acute Effects ◽  
Countermovement Jump ◽  
Jump Performance ◽  
Warm Up ◽  
Paired Samples ◽  
Jump Test ◽  
Significant Difference

The purpose of this study was to examine the acute effects of a dynamic warm-up including hip mobility exercises on sprint, agility and vertical jump performance. Twenty well trained male collegiate athletes (age = 20 ± 1.1 years; height = 178.3 ± 8.8 m; body weight = 72 ± 5.6 kg) volunteered for the study. All subjects completed two individual testing sessions on two non-consecutive days. On the first trial day, after 15 minutes of a simple dynamic warm-up, 30-m sprint test, Illinois agility test and countermovement jump test were performed at the control condition. On the second trial day addition to dynamic warm-up, subjects performed 6 hip mobility (6 min) exercises before tests. A paired samples t-test revealed a significant difference (p = 0.013) on sprint performance when comparing simple dynamic warm-up with a dynamic warm-up including hip mobility exercises. But no significant difference was found for agility (p = 0.071) and jump performances (p = 0.823). It can, therefore, be concluded that has a significant effect on sprinting performance whereas it has no significant effect on agility and vertical jump performance.

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