Countermovement Jump Research Articles

Assessing Isometric Midthigh Pull, Countermovement Jump, And Dynamic Strength Index In Active-duty Air Force Members

Assessing Isometric Midthigh Pull, Countermovement Jump, And Dynamic Strength Index In Active-duty Air Force Members

Relatioship Between Pelvic Belt Mid-Thigh Isometricpull And Countermovement Jump In Collegiate Athletes

Relatioship Between Pelvic Belt Mid-Thigh Isometricpull And Countermovement Jump In Collegiate Athletes

Impact Of Force Dampening Basketball Floors On Propulsive Kinetics During A Countermovement Jump

Impact Of Force Dampening Basketball Floors On Propulsive Kinetics During A Countermovement Jump

Does Taking a Break Matter-Adaptations in Muscle Strength and Size Between Continuous and Periodic Resistance Training.

We aimed to compare the effects of periodic resistance training (RT) and continuous RT on muscle strength and size. Fifty-five healthy, untrained participants (age 32 ± 5 years) were randomized to periodic (PRT, n = 20 completed the study, 45% females) or continuous (CRT, n = 22 completed the study, 45% females) groups. PRT completed a 10-week RT, a 10-week detraining, and a second identical 10-week RT. CRT began with a 10-week non-RT, followed by a 20-week RT. RT included twice-weekly supervised whole-body RT sessions. Leg press (LP) and biceps curl (BC) one repetition maximum (1RM), countermovement jump (CMJ) height, muscle cross-sectional area (CSA) of vastus lateralis (VL), and biceps brachii (BB) using ultrasound imaging were measured twice at the beginning and every fifth week during the intervention. Both groups increased (p < 0.001) 1RM in LP and BC, CSA in VL and BB, and CMJ height with no differences between the groups. In PRT, 1RM in LP and BC, CSA in VL and BB, and CMJ height decreased during detraining (p < 0.05). During the first 5 weeks of retraining in PRT, increases in LP 1RM, and VL and BB CSA were greater than in CRT during Weeks 10-15 of their CRT (p < 0.01). PRT and CTR ended up in similar postintervention adaptations, as decreased muscle strength and size during detraining in PRT regained rapidly during retraining. Our results therefore suggest that trainees should not be too concerned about occasional short-term training breaks in their daily lives when it comes to lifelong strength training. Trial Registration: ClinicalTrials.gov identifier: NCT05553769.

Force Plate Jump Assessment In The Military: Identifying Lower Body Capabilities During Countermovement Jumps

Force Plate Jump Assessment In The Military: Identifying Lower Body Capabilities During Countermovement Jumps

Alterations in hamstring properties of athletes with hamstring strain injuries can impact jump-landing performance.

Hamstring strains may alter the contractile properties of the muscle and affect functional movement. Thus, this study evaluated the association between the hamstring properties and the jump-landing performance in athletes with hamstring strains. Sixteen hamstring-injured athletes and 16 healthy controls were recruited. The mechanical properties and contractile function of the hamstring were assessed in both the injured and non-injured legs. The control group was tested only in the matched injured leg. The kinetic outcomes during squat jump (SJ) and countermovement jump (CMJ) tasks were analyzed to evaluate the jump-landing performance. The injured limb exhibited higher muscle tone (P=0.042) and stiffness (P=0.010), but lower flexibility (P=0.002) and strength (P=0.040) than the control limb. The injured limb showed a poorer jumping performance (P=0.037 for jump height) and landing performance (P=0.011 for landing force and P=0.004 for loading rate) during the CMJ task compared to the control limb. All the hamstring properties showed mild-to-moderate correlations with the jump-landing performance. Impairments in the muscle properties following hamstring strain impact the jumping and landing performance, leading to degraded sports outcomes in athletes with hamstring injuries. Thus, more attention should be paid to tissue property changes following hamstring strain injuries to develop effective strategies for restoring muscle function and improving sports performance.

Countermovement Jump Force Plate Kinetics In Collegiate Athletes With Overuse Injury Symptoms

Countermovement Jump Force Plate Kinetics In Collegiate Athletes With Overuse Injury Symptoms

Sex differences in upper and lower strength and their association with body composition among university students.

Sex strongly influences physical performance throughout adolescence, and excess fat mass is associated with several health and performance impairments. This study aimed to evaluate whether variations in strength between men and women dependent on lean mass and body fat content. This cross-sectional, quasi-experimental, non-probabilistic study involved 44 university students (22 men and 22 women, aged 19-29). Handgrip strength (HGS) was measured using an adjustable handgrip dynamometer, body composition was assessed using bioimpedance, and countermovement jumps (CMJ) were measured using a force platform. Data were analyzed using ANOVA to compare HGS and CMJ based on body mass, and the Pearson correlation coefficient was applied to examine the relationships between grip strength, body composition, and jump test performance. Strength is significantly higher in men compared to women, as is countermovement jump. The strength of women corresponded to over 50% of that of men, whereas the quantity of lean mass in women corresponded to 55% of that of men. We found a significant relationship between strength and lean mass. This study supports the idea that both upper- and lower-body strengths are strongly influenced by lean mass, thereby contributing to sex differences. The primary factor in body composition that explains the disparities in HGS and CMJ between sexes is the proportion of fat mass to lean mass. Finally, the sex disparities observed between body composition and strength depend on lean mass content.

Magnitude and Direction of Interlimb Asymmetry and the Association of Interlimb Asymmetry with Physical Performance in Judo Athletes with Visual Impairment.

For judo athletes with visual impairments and their coaches, understanding possible muscle adaptations can be challenging. As it is commonplace for these adaptations to include interlimb asymmetry, we analyzed the magnitude and direction of interlimb asymmetry in judo athletes with visual impairments and verified the association of this asymmetry with their unilateral physical performances. Participants were 18 elite judo athletes (10 male, 8 female) with visual impairments. These athletes performed three physical tests: countermovement jump (CMJ), medicine ball throw (MBT), and handgrip strength (HGS), while we conducted unilateral right and left side assessments using the interlimb asymmetry equation for each physical test. Our main results showed that the CMJ and MBT tests presented asymmetry values above 10%; with CMJ significantly higher than HGS (p = 0.050), and with inconsistencies across the three tests in the direction of interlimb asymmetry (k = -0.22-0.26). Unilateral CMJ (left limb) was negatively correlated with asymmetry (r = -0.51; p = 0.031), and unilateral MBT (right limb) was positively correlated with asymmetry (r = 0.52; p = 0.024). Based on these results, coaches should prioritize regular assessments of interlimb asymmetry using these specific tests. This data can guide the construction of training programs aimed at minimizing asymmetry and enhancing overall physical performance. Continuous monitoring and adjustment of training strategies based on asymmetry findings are crucial for optimizing muscle balance in judo athletes with visual impairments.

Mechanical power distribution of the lower limbs changed during intermittent 300 countermovement jumps.

The aim of this study was to investigate the effect of 300 intermittent countermovement jumps (CMJs) on the mechanical power distribution at the joints of the lower limbs and the influence of the upper body to explain vertical jump performance. Fifteen male sport students (age 24.5 ± 2.3years; body height 1.85 ± 0.06m; body mass 84.8 ± 8.5kg) performed a set of intermittent 300 CMJs at maximal effort. An inverse-dynamic approach was used to calculate the mechanical power at the hip, knee, and ankle joint for each jump. Jump height and mechanical power in the knee and ankle joints decreased significantly (p < .010), while remained the same in the hip joint. In contrast, a significant increased vertical velocity was observed for the upper body segment. In addition, a significant higher angular momentum at the center of mass was detected during the braking and propulsion phase. The findings highlight a fatigue-related decrease in lower limb power, particularly in the knee and ankle joints, which changed the mechanical power distribution at the joints of the lower limbs. The trunk extensor muscles were probably able to counteract the fatigue-related decrease in lower limb power by increased vertical velocity of the upper body segment and higher angular momentum at the center of mass during the braking and propulsion phase. Accordingly, the most effective way to maintain jumping performance in fatigued state would be to improve the fatigue resistance of the knee extensors, ankle plantar flexors, and trunk extensor muscles.

Increasing Braking and Amortization Forces during the Countermovement Jump Does Not Necessarily Improve Jump Height

Increasing Braking and Amortization Forces during the Countermovement Jump Does Not Necessarily Improve Jump Height

Intra- and inter-session reliability of countermovement jump and gait analysis in collegiate athletes measured using an inertial measurement unit (BTS G-Walk)

This study assessed the intra- and inter-session reliability of the inertial measurement unit (IMU) in measuring countermovement jump (CMJ) and 10m-walking gait-related outcomes. Thirty collegiate-level athletes (15 males [age: 21.0 ± 2.5 years] and 15 females [age: 21.5 ± 2.1 years]) were recruited to perform CMJs and 10m-walking test that were simultaneously recorded using the commercially available body-worn IMU – BTS G-walk. The coefficient of variation (CV), the analysis of variance with repeated measures (ANOVA), and the interclass correlation coefficient (ICC) were used for intra-session reliability. While the Pearson’s correlation coefficient (r) and the ICC were used to analyze inter-session reliability. Measurement of CMJ and 10m-walking test gait variables using the IMU resulted in moderate to excellent intra-session reliability for CMJ (ICC = 0.881 to 0.988) and gait analysis (ICC = 0.807 to 0.978) with acceptable CV (≤10%). Inter-session reliability for CMJ variables ranged from poor to excellent (ICC = 0.134 to 0.963), and 10-m walking test gait analysis variables were moderate to excellent (ICC = 0.683 to 0.931). The IMU (BTS G-walk) provides reliable data for most CMJ and gait variables. Future studies may determine the accuracy of the equipment to monitor changes over time (e.g., after a training intervention).

Which jump test is most sensitive for classifying ACL injury history in fatigued or non-fatigued athletes?

Introduction &amp; Purpose In fast-paced clinical decision-making, jump-landing movement assessments are rarely used to guide return-to-sport (RTS) decisions after an anterior cruciate ligament (ACL) injury. While these tests are crucial for identifying deficits in movement execution (e.g., dynamic valgus, extended knee, knee internal rotation) that could predispose to ACL re-rupture (Kaplan &amp; Witvrouw, 2019), identifying these deficits can be challenging. To integrate RTS movement assessments into clinical practice, the first step is to identify the most sensitive jump-landing test that can best expose remaining deficits in neuromuscular control and resulting landing kinematics associated with ACL injury. Further, RTS tests are mostly performed in a non-fatigued state although fatigued individuals often fail to reach the RTS criteria (Dingenen &amp; Gokeler, 2017). This exploratory study aimed to rank common jump-landing tests in their ability to identify (sensitivity and classification rate) deficits in whole-body landing kinematics following ACL injury, under both fatigued and non-fatigued conditions. Methods A total of 43 volunteers were recruited into ACL group (n = 21, 11 females, 3.9 years post ACL injury) and control group (n = 22, 12 females). 3D motion data (Vicon, 250 Hz) were recorded during a single-leg forward hop (SH), single-leg countermovement jump (CMJ), single-leg triple crossover hop (COH), and single-leg 90° medial rotation hop (MRH) before and after a fatigue-inducing intervention (single-leg squats and step-ups). Thirteen joint angles (50 ms after initial contact) from the lower body, trunk, and pelvis representing the landing kinematics were calculated in OpenSim. A correlation analysis was performed to check for multicollinearity issues. Eight distinct logistic regression models (four jumps, fatigued/non-fatigued, α = .05) were computed to predict ACL injury history based on a combination of joint angles. For each model, a backward stepwise method was employed to determine which combination of joint angles resulted in the highest classification rates. Results ACL injury history was successfully predicted in seven (χ² &gt; 4.4, p &lt; .036) of the eight logistic regression models (Figure 1). The SH in the fatigued condition (χ² = 22.5, p = .008) demonstrated the highest sensitivity of 85.7% and a classification rate of 86%. Significant predictors for this model were knee rotation (Odds ratios [OR] = 1.537), hip abduction (OR = 1.385), hip rotation (OR = 1.525), and ankle flexion (OR = 0.771). The CMJ (non-fatigued) showed the second-highest sensitivity of 81% and a classification rate of 81.4% (p = .027). Significant predictors were knee rotation (OR = 1.440), hip abduction (OR = 1.428), hip rotation (OR = 1.297), and pelvis rotation (OR = 0.664). The MRH in the non-fatigued condition exhibited the lowest sensitivity, and no classification was possible in the non-fatigued COH model (χ² = 3.6, p = .056). Discussion &amp; Conclusion The fatigued SH was the most sensitive jump-landing test for classifying groups and detecting kinematic differences due to previous ACL injury. Thus, we recommended the SH over other tests for RTS decision-making, as it is most likely to reveal kinematic abnormalities. Higher classification rates in the fatigued condition support RTS testing in fatigued states to better identify movement deficits. To integrate jump-landing assessments into RTS decisions in a feasible way, our future work will involve 3D motion capture using pose estimation algorithms on video data.

Effect of repeated use of social media before training sessions on countermovement jumping and internal training load in high-level volleyball players

To verify the effect of repeated use of social media on smartphones immediately before countermovement jump (CMJ) and internal training load (ITL) training sessions in young male high-level volleyball athletes. 18 young international-level athletes participated in a randomized crossover study for a total of two weeks. The athletes are from the Brazilian under-19 team and were randomized into two experimental conditions, social media (SMA) and control (CON). SMA used social media for 30 minutes before training sessions for a week, while CON watched emotionally neutral videos. During this period, the ITL was analyzed using the session rating of perceived exertion (s-RPE) method. The CMJ was analyzed before, between, and after the two-week training. In the second week, the athletes reversed the experimental conditions. The CMJ was decreased after the training week (p = 0.04), but with no difference between the experimental conditions (p = 0.51). The ITL was not different between the experimental conditions after the analyzed training week (p = 0.95). Repeated use of social media on smartphones immediately before training sessions for a week was not enough to harm the CMJ, nor did it increase the ITL in young international-level volleyball athletes. Verificar el efecto del uso repetido de redes sociales en teléfonos inteligentes inmediatamente antes de las sesiones de entrenamiento en salto con contra-movimiento (SCM) y carga de entrenamiento interna (CEI) en jóvenes atletas masculinos de voleibol de alto nivel. 18 atletas jóvenes de notoriedad mundial participaron en un estudio cruzado y aleatorizado durante un total de dos semanas. Los atletas son de la selección brasileña sub-19 y fueron distribuidos aleatoriamente en dos condiciones experimentales, redes sociales (TEL) y control (CON). La TEL utilizó las redes sociales durante 30 minutos antes del entrenamiento durante una semana, mientras que la CON vio vídeos emocionalmente neutros. Durante este período, el CEI se analizó mediante el método de percepción subjetiva del esfuerzo de la sesión. El SCM se analizó antes e después del entrenamiento de una semana. En la segunda semana, los atletas invirtieron las condiciones experimentales. El SCM disminuyó después de la semana de entrenamiento (p = 0,04), pero sin diferencias entre las condiciones experimentales (p = 0,51). El CEI no fue diferente entre las condiciones experimentales después de la semana de entrenamiento analizada (p = 0,95). El uso repetido de las redes sociales en los teléfonos inteligentes inmediatamente antes del entrenamiento durante una semana no fue suficiente para afectar la SCM, ni aumentó la CEI en jóvenes atletas de voleibol de nivel internacional. Verificar o efeito do uso repetido de redes sociais em smartphones imediatamente antes de sessões de treinamento do salto com contramovimento (SCM) e carga interna de treinamento (CIT) em jovens atletas masculinos de voleibol de alto nível. 18 jovens atletas de nível internacional participaram de um estudo cruzado e randomizado durante um total de duas semanas. Os atletas são da seleção brasileira sub-19 e foram randomizados em duas condições experimentais, redes sociais (SMA) e controle (CON). O SMA usou as redes sociais por 30 minutos antes dos treinos durante uma semana, enquanto o CON assistia vídeos emocionalmente neutros. Nesse período, o CIT foi analisado através do método da percepção subjetiva do esforço da sessão (PSE-s). O SCM foi analisado antes, entre e após o treinamento de duas semanas. Na segunda semana, os atletas inverteram as condições experimentais. O SCM diminuiu após a semana de treinamento (p = 0,04), mas sem diferença entre as condições experimentais (p = 0,51). O CIT não foi diferente entre as condições experimentais após a semana de treinamento analisada (p = 0,95). O uso repetido de redes sociais em smartphones imediatamente antes dos treinos durante uma semana não foi suficiente para prejudicar o SCM, nem aumentou a CIT em jovens atletas de voleibol de nível internacional.

Countermovement Jump Peak Power Changes with Age in Masters Weightlifters.

Aging is associated with decreased muscle strength and power. Power is particularly important for maintaining the independence of older adults when performing activities of daily living. The countermovement jump has been identified as a reliable and safe method to assess lower extremity power across the lifespan. The purpose of this investigation was to study sex differences and age-related changes in countermovement jump peak power among masters weightlifters with the secondary purpose of comparing results to previous reports of community and masters athletes. Female (n = 63, 39 to 70 yrs, med (56 yrs)) and male (n = 39, 35 to 86 yrs, med (59 yrs)) participants of the 2022 World Masters Championships completed three maximal effort countermovement jump repetitions following a dynamic warm-up. Vertical ground reaction forces were recorded, and peak power normalized to body mass was calculated. Results indicated significant age-related peak power among weightlifters, with the decline being significantly more pronounced in males than females. Female weightlifters exhibited less age-related decline compared to normative data as well as the other Master athlete comparison cohorts (short and long-distance runners), whereas the males demonstrated similar age-related declines as the comparison cohorts. While the female weightlifters in the current study generally demonstrated the least age-related declines in CMJ peak power of the comparative literature, the male weightlifters showed similar age-related decline rates.

Effects of Caffeinated Chewing Gum on Ice Hockey Performance after Jet Lag Intervention: Double-Blind Crossover Trial.

The purpose of this study was to examine the impact of caffeinated chewing gum on the physical performance of elite ice hockey players after a jet lag intervention. Fourteen national-level (age: 25.2 ± 5.4; height: 176.5 ± 5.3; weight: 78.1 ± 13.4) ice hockey players were tested late at night after a full day awake schedule with jet lag. A randomised, double-blind experimental design was employed in which participants either chewed caffeinated gum (CAF) containing 3 mg/kg caffeine or a caffeine-free placebo gum (PLA) for 10 min prior to undertaking a series of on-ice and off-ice tests. The off-ice tests included grip force, the counter-movement jump (CMJ), and the squat jump (SJ). The on-ice tests included a 35 m sprint, the S-Shape agility test, and the Yo-Yo intermittent recovery test (Yo-Yo IR1 test). The CMJ height (CAF: 47.2 ± 4.4; PL: 45.9 ± 3.5; p = 0.035; Cohen's d = 0.32) and SJ height (CAF: 46.7 ± 4.1; PL: 44.9 ± 3.8; p = 0.047; Cohen's d = 0.44) were found to be significantly higher in the CAF than in the PL trial. However, there were no significant differences (p > 0.05) in grip force, as well as in the 35 m sprint, the S-Shape agility test, and the Yo-Yo IR1 test. The present study found that, following a jet lag intervention, although the consumption of caffeinated gum resulted in an increase in vertical jump height, it had no impact on performance in the ice tests. The results of this study may help coaches and athletes consider the need for caffeine supplementation when experiencing jet lag.

Dietary intake, energy availability, and power in men collegiate gymnasts.

The purpose was to examine the prevalence of low energy availability (LEA), explore dietary behaviors in men collegiate gymnasts (n = 14), and investigate the relationships between energy availability (EA), body composition, and plyometric performance. Body composition was measured using air displacement plethysmography. Lower- and upper-body peak power (PWRpeak) and modified reactive strength index (RSImod) were calculated from countermovement jump (CMJ) and plyometric push-up (PP) assessments. Energy expenditure was tracked over 3 days, while daily energy and macronutrient intake were recorded. EA was calculated and used to categorize athletes into LEA and non-LEA groups. Pearson correlation coefficients were used to examine relationships between EA, body composition, and performance metrics. 85.7% of athletes (n = 12) exhibited LEA (20.98 ± 5.2 kcals/kg FFM), with non-LEA athletes (n = 2) marginally surpassing the <30 kcal/kg of fat-free mass (FFM) threshold (30.58 ± 0.2 kcals/kg FFM). The cohort (n = 14) consumed insufficient energy (30.5 ± 4.5 kcal/kg/day) and carbohydrates (3.7 ± 1.1 g/kg/day), resulting in LEA (22.36 ± 5.9 kcal/kg/FFM). EA was not correlated with body composition or performance metrics. A high prevalence of LEA may exist in men gymnasts, largely due to a low relative energy and carbohydrate intake.

Seasonal Comparison of Pre-Adolescent Soccer Players' Physical Performance Using an Objective Physical Test Battery.

Soccer is a multifactorial sport, requiring physical, psychological, technical, and tactical skills to succeed. Monitoring and comparing physical characteristics over time is essential to assess players' development, customize training, and prevent injury. The use of wearable sensors is essential to provide accurate and objective physical data. In this longitudinal study, 128 male adolescent soccer players (from Under 12 to Under 19) were evaluated at two time points (pre- and post-season). Participants completed the Euleria Lab test battery, including stability, countermovement and consecutive jumps, agility, and quick feet tests. A single Inertial Measurement Unit sensor provided quantitative data on fifteen performance metrics. Percentage changes were compared to the Smallest Worthwhile Changes to assess significant changes over time. The results showed significant improvements in most variables, including a 19.7% increase in quick feet, 10.9% in stability, and 9.6% in countermovement jumps. In principal component analysis, we identified four principal components-strength-power, balance, speed-agility, and stiffness-that explained over 80% of the variance. These findings align with previous studies assessing seasonal changes in adolescent soccer players, showing that the proposed test battery seems to be adequate to highlight physical performance changes and provide coaches with meaningful data to customize training and reduce injury rates.

Assessing lower extremity stiffness in countermovement jumps: a critical analysis of the differences between calculation methods

ABSTRACT Introduction: Stiffness (k) describes a material’s resistance to deformation and is useful for understanding neuromuscular function, performance, and injury risk. The aim of this study is to compare the lower limb stiffness method (k LLS ), which uses only force plate data, with methods combining force plate and motion capture data to calculate stiffness during the eccentric phase of a countermovement. Material and Methods: Twelve resistance-trained males: age 24.9 (4.4) years, height 1.81 (0.05) m, weight 88.2 (14) kg) performed three maximal effort countermovement jumps (CMJ). Data were collected synchronously using three-dimensional (3D) kinematic and kinetic data (dual force plate setup). Lower limb stiffness (z), joint stiffness (x, y, and z), and leg stiffness (linear, sagittal plane, and 3D) were calculated for the eccentric phase of all CMs. Results: k LLS showed high concurrent validity with strong correlations to kinetic-kinematic methods (r = 0.90-0.97, p < 0.05). A linear mixed model revealed no significant differences in k-values between k LLS and leg stiffness, indicating high concurrent validity. Discussion: k LLS offers valid and valuable information affecting performance, injury risk, and return-to-sport decisions. Conclusion: The findings suggest that k LLS is a valid method for calculating stiffness in CMJs and equal to 3D leg stiffness.

Assessing physical fitness adaptations in collegiate male soccer players through training load parameters: a two-arm randomized study on combined small-sided games and running-based high-intensity interval training.

To evaluate the effects of a 4-week intervention combining small-sided games (SSGs) and high-intensity interval training (HIIT) on physical fitness in collegiate male soccer players. Twenty-one soccer players were randomly assigned to either the HIIT + SSGs group (n = 11) or a control group (n = 10). Physical fitness was assessed at baseline and 1-week post-intervention, including countermovement jump (CMJ), change of direction (COD) test, sprint test, repeated sprint ability (RSA) test, and 30-15 Intermittent Fitness Test (30-15IFT). The intervention comprised eight sessions over 4weeks: four SSGs and four HIIT. The intervention group showed small to moderate improvements: mean RSA improved by 4.5% (p = 0.07), CMJ increased by 3.2% (p = 0.12), and 30-15IFT scores enhanced by 6.8% (p = 0.09). Key predictors of group membership included heart rate load per minute (OR 1.602) and various GPS variables. The 4-week intervention combining SSGs with HIIT did not produce statistically significant improvements in most physical fitness variables compared to the control group. Although there were positive trends in variables such as RSA and 30-15IFT, these changes were modest and not statistically significant. The results suggest that while the combined SSGs and HIIT approach shows potential, its impact on physical fitness over a 4-week period is limited, with some variables, like CMJ, even showing decreases.