A new approach to determining net impulse and identification of its characteristics in countermovement jumping: reliability and validity |
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| Authors: | Satoshi Mizuguchi William A Sands Craig A Wassinger Hugh S Lamont Michael H Stone |
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| Institution: | 1. Department of Exercise and Sport Science, East Tennessee State University, Johnson City, TN, USA;2. Center of Excellence for Sport Science and Coach Education, East Tennessee State University, Johnson City, TN, USAharahara10@hotmail.com;4. Center of Excellence for Sport Science and Coach Education, East Tennessee State University, Johnson City, TN, USA;5. Department of Physical Therapy, East Tennessee State University, Johnson City, TN, USA;6. Department of Exercise Science, California Lutheran University, Thousand Oaks, CA, USA;7. Center of Excellence for Sport Science and Coach Education, East Tennessee State University, Johnson City, TN, USA |
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| Abstract: | Examining a countermovement jump (CMJ) force-time curve related to net impulse might be useful in monitoring athletes' performance. This study aimed to investigate the reliability of alternative net impulse calculation and net impulse characteristics (height, width, rate of force development, shape factor, and proportion) and validate against the traditional calculation in the CMJ. Twelve participants performed the CMJ in two sessions (48 hours apart) for test–retest reliability. Twenty participants were involved for the validity assessment. Results indicated intra-class correlation coefficient (ICC) of ≥ 0.89 and coefficient of variation (CV) of ≤ 5.1% for all of the variables except for rate of force development (ICC = 0.78 and CV = 22.3%). The relationship between the criterion and alternative calculations was r = 1.00. While the difference between them was statistically significant (245.96 ± 63.83 vs. 247.14 ± 64.08 N s, p < 0.0001), the effect size was trivial and deemed practically minimal (d = 0.02). In conclusion, variability of rate of force development will pose a greater challenge in detecting performance changes. Also, the alternative calculation can be used practically in place of the traditional calculation to identify net impulse characteristics and monitor and study athletes' performance in greater depth. |
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| Keywords: | Force plate ground reaction force force-time curve |
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