Effect of Landing Posture on Jump Height Calculated from Flight Time

Yamashita, Daichi; Murata, Masahide; Inaba, Yuki

doi:10.3390/app10030776

Cited by 19 publications

(11 citation statements)

References 34 publications

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“…Aside from the 1FP method demonstrating criterion validity when predicting actual DH and touchdown velocity, there was also no fixed or proportional bias for any of the DJ performance variables reported (Tables 1 and 2). The comparable jump heights between methods were estimated from take-off velocity which is positive as it eliminates the error associated with flight time-estimated jump height due to differences in take-off and landing posture [24]. This is why the accuracy of the 1FP method for determining DH [5,10] which involves predicting propulsion net impulse from flight-time estimated jump height and then subtracting this from the entire net impulse to predict braking net impulse (and then using braking net impulse to predict DH), can be questionable [7,8].…”

Section: Resultsmentioning

confidence: 99%

A Proposed Method for Evaluating Drop Jump Performance with One Force Platform

et al. 2021

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The drop jump (DJ) is commonly utilised to assess athletes. The criterion two force platform (2FP) method of assessing DJ performance involves two adjacent force platforms, one for the box and one for the athlete to rebound from. Most researchers and practitioners only have access to one force platform (1FP) and they rarely account for the often considerable discrepancy between box height and drop height (DH). Therefore, this study aimed to determine the criterion validity of evaluating DJ performance with 1FP. Twenty-six young male sports students performed three DJs, from a 0.30 m and 0.40 m high box, on two adjacent force platforms. The DH, touchdown velocity and several performance variables were calculated using the 2FP and 1FP methods. Ordinary least-products regression identified no fixed or proportional bias between methods for any DJ variable. The mean DH was 10% lower than the 0.30 m box and 14% lower than the 0.40 m high box. This discrepancy highlights the importance of accounting for DH when conducting DJ assessments. In conclusion, the 1FP method of evaluating DJ performance is a valid alternative to the criterion 2FP method and could be embedded into automated force analysis software for researchers and practitioners to utilise.

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Section: Resultsmentioning

confidence: 99%

A Proposed Method for Evaluating Drop Jump Performance with One Force Platform

et al. 2021

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“…Consequently, the dependent variables of forward dynamics procedures (e.g., velocity and power values) are affected to a greater extent by an inaccurate determination of the body weight during the bilateral CMJ [20]. By contrast, other variables that do not depend on the calculation of body weight, such as mean and peak force, were obtained with higher reliability during the bilateral CMJ [40,41]. These findings are partially in line with Bishop et al [19] who found a higher reliability (CV ratio = 1.29-1.63) for the bilateral CMJ compared to the unilateral CMJ in single-leg strength performance (mean force and concentric impulse).…”

Section: Plos Onementioning

confidence: 99%

Between-session reliability of performance and asymmetry variables obtained during unilateral and bilateral countermovement jumps in basketball players

et al. 2021

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This study aimed to evaluate the between-session reliability of single-leg performance and asymmetry variables during unilateral and bilateral countermovement jumps (CMJ). Twenty-three basketball players completed two identical sessions which consisted of four unilateral CMJs (two with each leg) and two bilateral CMJs. Mean and peak values of force, velocity and power, impulse, and jump height were obtained separately for each leg using a dual force platform. All performance variables presented an acceptable reliability (CVrange = 4.05–9.98%) with the exceptions of jump height for the unilateral CMJs and mean power, peak velocity, peak power, and impulse for the left leg during the bilateral CMJ (CV≥11.0%). Nine out of 14 variables were obtained with higher reliability during the unilateral CMJ (CVratio≥1.16), and 4 out of 14 during the bilateral CMJ (CVratio≥1.32). Asymmetry variables always showed an unacceptable reliability (ICCrange = 0.15–0.64) and poor/slight levels of agreement in direction (Kapparange = -0.10 to 0.15) for the unilateral CMJ, while an acceptable reliability (ICCrange = 0.74–0.77) and substantial levels of agreement in direction (Kapparange = 0.65 to 0.74) were generally obtained for the bilateral CMJ. These results suggest that single-leg performance can be obtained with higher reliability during the unilateral CMJ, while the bilateral CMJ provides more consistent measures of inter-limb asymmetries.

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“…For accelerometers, the inclusion of a gyroscope may account for landing position and trunk inclination [ 11 ], while linear transducers are advised to be set-up as vertical as possible. On the other hand, camera-based apps and micro-lasers use flight time primarily to calculate jump height, and therefore rely on proper jump and landing mechanics for accuracy [ 12 ]. The main difficulty with body-mounted accelerometers and camera-based applications is the correct identification of take-off and landing [ 13 ].…”

Section: Introductionmentioning

confidence: 99%

Concurrent Validity and Reliability of Three Ultra-Portable Vertical Jump Assessment Technologies

Watkins

Maunder

Tillaar

et al. 2020

Sensors

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Vertical jump is a valuable training, testing, and readiness monitoring tool used across a multitude of sport settings. However, accurate field analysis has not always been readily available or affordable. For this study, two-dimensional motion capture (Mo-Cap), G-Flight micro-sensor, and PUSH accelerometer technologies were compared to a research-grade force-plate. Twelve healthy university students (7 males, 5 females) volunteered for this study. Each participant performed squat jumps, countermovement jumps, and drop jumps on three separate occasions. Between-device differences were determined using a one-way repeated measures ANOVA. Systematic bias was determined by limits of agreement using Bland–Altman analysis. Variability was examined via the coefficient of variation, interclass correlation coefficient, and typical error of measure. Dependent variables included jump height, contact-time, and reactive strength index (RSI). Mo-Cap held the greatest statistical similarity to force-plates, only overestimating contact-time (+12 ms). G-Flight (+1.3–4 cm) and PUSH (+4.1–4.5 cm) consistently overestimate jump height, while PUSH underestimates contact-time (−24 ms). Correspondingly, RSI was the most valid metric across all technologies. All technologies held small to moderate variably; however, variability was greatest with the G-Flight. While all technologies are practically implementable, practitioners may want to consider budget, athlete characteristics, exercise demands, set-up, and processing time before purchasing the most appropriate equipment.

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Effect of Landing Posture on Jump Height Calculated from Flight Time

Cited by 19 publications

References 34 publications

A Proposed Method for Evaluating Drop Jump Performance with One Force Platform

A Proposed Method for Evaluating Drop Jump Performance with One Force Platform

Between-session reliability of performance and asymmetry variables obtained during unilateral and bilateral countermovement jumps in basketball players

Concurrent Validity and Reliability of Three Ultra-Portable Vertical Jump Assessment Technologies

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