Single-leg Vertical Jumps Research Articles

Normative Data and the Influence of Age and Gender on Power, Balance, Flexibility, and Functional Movement in Healthy Service Members

Determine the influence of age and sex and describe normative data on field expedient tests associated with power, balance, trunk stability, mobility, and functional movement in a military population. Participants (n = 247) completed a series of clinical and functional tests, including closed-chain ankle dorsiflexion (DF), Functional Movement Screen (FMS), Y-Balance Test Lower Quarter (YBT-LQ), Y-Balance Test Upper Quarter (YBT-UQ), single leg vertical jump (SLVJ), 6-m timed hop (6-m timed), and triple hop. Descriptive statistics were calculated. Analysis of variance tests were performed to compare the results based on sex and age (<30 years, >30 years). Service members demonstrated DF of 34.2 ± 6.1°, FMS composite score of 16.2 ± 2.2, YBT-LQ normalized composite score of 96.9 ± 8.6%, YBT-UQ normalized composite score of 87.6 ± 9.6%, SLVJ of 26.9 ± 8.6 cm, 6-m hop of 2.4 ± 0.5 seconds, and a triple hop of 390.9 ± 110.8 cm. Men performed greater than women (p < 0.05) on the YBT-LQ, YBT-UQ, SLVJ, 6-m timed, and triple hop. Those <30 years of age performed better than older participants (p < 0.05) on the DF, FMS, YBT-LQ, SLVJ, 6-m hop, and triple hop. Findings provide normative data on military members. Men performed better on power, balance, and trunk stability tests, whereas younger individuals performed better on power, balance, mobility, and functional movement.

Correlation of single leg vertical jump, single leg hop for distance, and single leg hop for time

Objectives To determine the correlation among three functional tests: single leg vertical jump (SLVJ), single leg hop for distance (SLHD), and single leg hop for time (SLHT). Design Prospective correlational investigation. Setting University research laboratory. Participants Forty healthy men ( n = 19) and women ( n = 21) between the ages of 18 and 30 (23.9 ± 2.0 years). Main outcome measures SLVJ was measured using the Vertec. SLHD was measured using a standard tape measure. SLHT was measured over a 10-m course using a standard stopwatch. Results The strongest correlation was between SLHT and SLHD, −0.89 and −0.89 for dominant and non-dominant lower extremities (LE), respectively. The weakest pairwise correlation was between SLVJ and SLHT, −0.71 and −0.63 for dominant and non-dominant LE, respectively. The correlation between SLVJ and SLHD was 0.74 and 0.71 for dominant and non-dominant LE, respectively. Conclusion There is a strong correlation between SLHT and SLHD, suggesting that each test measures similar constructs of function, while the modest correlation between SLVJ and SLHT suggest these two tests do not measure the same functional components, and could be paired as outcome measures for the clinical assessment of lower extremity function.

ACL Research Retreat V

ACL Research Retreat V

Bilateral Comparison of Propulsion Mechanics During Single-Leg Vertical Jumping

The primary purpose of this investigation was to compare single leg vertical jump performance and several performance characteristics derived from vertical ground reaction forces (vGRF) between the dominant (DOM) and nondominant (NDOM) legs. Secondary purposes included determining the relationship between the kinetic and temporal characteristics and single leg vertical jump performance and establishing the intrasession and intersession reliability of the characteristics considered. After a standardized warm-up, 20 physically active young adults (10 men, 10 women) performed three single leg DOM and three single leg NDOM vertical jumps in a random order during two sessions separated by three days. vGRF collected during each trial were used to calculate jump height, peak vertical power, peak vGRF, vGRF impulse, ratio between negative to positive vGRF impulse, time between maximum peak power to takeoff and countermovement depth. There were no significant differences between DOM and NDOM for jump height (p = .145) as well as the six characteristics considered (p > .05). There was a strong, direct relationship between jump height and peak vertical power for both DOM (r = .915, p < .001) and NDOM (r = .944, p < .001). With the exception of vGRF negative/positive impulse ratio, all dependent variables demonstrated moderate to high intrasession and intersession reliability. These results support using a single leg vertical jump protocol for conducting bilateral lower extremity functional assessments. With the exception of impulse ratio, the reliability results support using the protocol for serial assessments. In conclusion, healthy individuals can be expected to exhibit near equal single leg vertical jumping performance bilaterally, providing practitioners with a basis to interpret performance.

Bilateral Comparison of Propulsion Mechanics during Single Leg Vertical Jumping

PURPOSE: To compare single leg vertical jump propulsion mechanics between the dominant (DOM) and non-dominant (NDOM) limbs. METHODS: After a standardized warm-up, 20 (10 men, 10 women) physically active (Tegner score=6.5±1.7, range:4-9) young adults (21.7± 2.1yrs) performed three single leg DOM and three single leg NDOM vertical jumps in random order. Ground reaction forces were collected during each trial and used to establish vertical force, velocity, displacement, and power curves. Five variables were calculated: jump height (based on takeoff velocity), depth of countermovement (DCM), peak force (PF) normalized to body weight (BW), peak positive power (PPP) normalized to BW, and the ratio of negative to positive impulse. Bilateral comparisons and correlations, were conducted using trial one data, while reliability of the variables was assessed across the three trials using intraclass correlation coefficients (2,1) and standard error of measurement (SEM). RESULTS: A non-significant trend (P=.057) for greater jump height was identified for the NDOM (15.6±4.5cm, 95% CI:13.5-17.7cm), versus DOM (14.7±3.9cm, 95% CI:12.9-16.5cm) limb. The other variables were statistically (P>.05) equal bilaterally. There was high positive correlation between jump height and PPP for both DOM (r=.915, P<.001) and NDOM (r=.944, P<.001) jump height. Other variables related to jump height were vertical maximum positive ground reaction force (DOM: r=.486, P=.03, NDOM: r=.513, P=.021) and DCM (DOM: r=.407, P=.075, NDOM: r=.495, P=.027). Results of the reliability analyses demonstrated highest reliability (ICC,SEM) for jump height (DOM=.974, 1.16cm; NDOM=.919, 1.30cm), PPP (DOM= .871, .195W/ BW, NDOM=.880, .196W/BW), and PF (DOM=.738, .111BW, NDOM=.755, .100BW). CONCLUSION: The results suggest that near equal jump heights may be expected when conducting bilateral comparisons in healthy individuals. Similar to previous reports examining double leg vertical jumping, PPP appears to be the best predictor of jump height followed by PF. Bilateral comparison data can be used as guidelines for preseason screening to identify potential asymmetry, guidelines for criteria for serial assessment for exercise prescription and rehabilitation and parameters for discharge for rehabilitation.

Validity of Double-and Single-Leg Vertical Jumps as Tests of Leg Extensor Muscle Function

The purpose of this research was to determine if 5 weeks of resistance training for the shoulder and hip flexor muscles produces improvements in vertical jumping (VJ) performance. Twenty-eight men were assessed on tests of shoulder power, leg extensor muscle function, and VJ performance using jumps performed from a standing position, a 3-stride run-up, and double-and single-leg takeoffs. A shoulder and hip flexor training group (n = 14) improved significantly more than a nontraining control group (n = 12) in shoulder power and 2 VJ performance tests, but not in the tests of leg extensor muscle function. It was concluded that the arm swing and free-leg drive significantly influence VJ performance and, therefore, VJ tests are not valid for assessment of leg extensor muscle function.

Validity of Double- and Single-Leg Vertical Jumps as Tests of Leg Extensor Muscle Function

The purpose of this research was to determine if 5 weeks of resistance training for the shoulder and hip flexor muscles produces improvements in vertical jumping (VJ) performance. Twenty-eight men were assessed on tests of shoulder power, leg extensor muscle function, and VJ performance using jumps performed from a standing position, a 3-stride run-up, and double- and single-leg takeoffs. A shoulder and hip flexor training group (n = 14) improved significantly more than a nontraining control group (n = 12) in shoulder power and 2 VJ performance tests, but not in the tests of leg extensor muscle function. It was concluded that the arm swing and free-leg drive significantly influence VJ performance and, therefore, VJ tests are not valid for assessment of leg extensor muscle function.

The effects of serial stretch loading on stretch work and stretch-shorten cycle performance in the knee musculature.

Training methods to optimize stretch-shorten cycle performance and an active muscle's ability to resist a sudden stretch (stretch work) and the relationship between the two have not been fully explored. The purpose of this study was to examine the effects of an 8-week strengthening program of serial stretch loading on stretch work and stretch-shorten cycle performance in the quadriceps and hamstring muscles. Thirty-one asymptomatic subjects participated in pre- and post-tests of maximum voluntary isometric contractions, stretch work and stretch-shorten cycle trials, and single-leg vertical jumps. The training portion consisted of progressively resisted isotonic single-leg squats. One leg exercised against an isotonic load with serial stretch loading, while the other leg exercised against isotonic load alone. Training resulted in strength gains in both legs indicated by the increase in weight lifted during training, but not by maximum voluntary isometric contractions. Vertical jump height increased in both legs. In the hamstring, stretch work decreased and stretch-shorten cycle performance increased in both legs. In the quadriceps, serial stretch loading intervention resulted in increased stretch-shorten cycle performance and no significant change in stretch work. The correlation between stretch-shorten cycle and stretch work was weak but significant. These findings suggest that the use of serial stretch loading could improve muscular performance and enhance a muscle's potential for dynamic stabilization.