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Speed/Power Development

(13) MUSCULAR STRENGTH CHARACTERISTICS OF THE ISOMETRIC MID-THIGH PULL IN COLLEGIATE AMERICAN FOOTBALL ATHLETES, STARTERS VS. NON-STARTERS

Friday, July 12, 2024
1:00 PM – 1:15 PM East Coast USA Time
Location: Room 337-338
Abstract Details: Introduction: Within American football, athletic performance characteristics such as muscular strength and muscular power typically distinguish starters from non-starters (Fry & Kraemer, 1991). The isometric mid-thigh pull (IMTP) is one such method of measuring muscular strength. Limited data exist regarding strength and power differences between starters and non-starters in American football using IMTP as the mean of measurement. PURPOSE: To assess differences in collegiate American football athletes' IMTP force-time characteristics between starters and non-starters. METHODS: 24 National Collegiate Athletic Association Division II American football athletes volunteered for the study and were divided into the starter group (n=11, x̅±SD; height=190.04±3.91 cm; weight=118.44±27.38 kg) and non-starter group (n=13, x̅±SD; height=188.16±6.84 cm; weight=109.67±27.54 kg). Following a standardized dynamic warm-up, athletes performed two maximal effort IMTPs on a 1000 Hz sampling rate dual force plate system. The vertical ground reaction force of each IMTP was recorded. Means and standard deviations were calculated for all variables recorded. An independent samples T-test was performed on all variables recorded by the dual force plate system and a Shapiro-Wilks test was also conducted to confirm normality. The a-priori alpha level was set at 0.05 for all analyses. Hedge’s g was used for effect sizes. RESULTS: Time to peak force (p=0.020, g=-0.63), force at 150ms (p=0.045, g=0.51), right force at 150ms (p=0.006, g=0.77), and relative peak force (p=0.017, g=-0.65) significantly differed between groups with better values for each metric being recorded for starters compared to non-starters except for relative peak force. Impulse and rate of force development (RFD) did not show significant differences between groups (p=0.072-0.391, g=-0.091-0.441). CONCLUSIONS: Within this cohort, starters produced isometric forces more efficiently (i.e. in less time) when compared to non-starters. However, non-starters produced higher isometric peak forces than the starter group, possible cause may be due to individual’s familiarity with the IMTP protocol. Also noteworthy is that both groups favored their right side during the IMTP task. After adequate muscular strength has been developed, sports performance professionals should emphasize maximal force production relative to time and RFD to prepare non-starters for starting roles. PRACTICAL APPLICATIONS: With the utilization of force plate technology, the IMTP assessment provides detailed information in regard to muscular strength characteristics in American football athletes which can provide unique insights that can be leveraged to improve athletes' development, progression, and sports performance both on the short and long term.  

Acknowledgements: This project was funded in part by the Wu Tsai Human Performance Alliance and the Joe and Clara Tsai Foundation, and by the University of Nebraska at Kearny's INSpRE Instrumentation Core.