Matthew J. Hermes1, Jonathan D. Miller2, & Andrew C. Fry

1Murray State University, Murray, Kentucky; 2The University of Kansas, Lawrence, Kansas

One repetition max (1RM) testing is used to assess strength performance. Previous work suggests variables like eccentric velocity influence 1RM performance, with faster eccentric velocities contributing to better 1RM performances. Further, concentric velocity has been suggested as a means to predict 1RM. However, limited work has compared 1RM performance between stronger (ST) and weaker (WK) lifters. PURPOSE: To compare 1RM kinematic performance differences between ST and WK lifters. METHODS: Recreationally trained males (n=14) completed bench press (BP) 1RM testing. Post hoc, participants were split into ST (n=7, age=23.4±3.5 yrs, ht=174.4±6.2 cm, wt=86.0±11.7 kg, relative 1RM=1.45±0.07) and WK (n=7, age=23.6±3.0 yrs, ht.=176.5±10.7 cm, wt.=90.4±15.1 kg, relative 1RM=1.06±0.04) groups. To divide participants, median relative 1RM was calculated. Those below and above the median were placed in WK and ST, respectively. Bar displacement and time data were collected with a linear position transducer sampling at 1000 Hz. Mean eccentric (ECCV) and concentric velocity (CONV), and relative mean and peak eccentric and concentric force were derived from bar position-time data. An independent samples t-test was used to assess group differences for relative 1RM, eccentric (ECCD) and concentric duration (COND), ECCV, CONV, and relative force variables (p<.05). RESULTS: Relative 1RM was higher in ST (p<.001, g=6.42), though body mass (BM) was similar (p=.55, g=.31). Self-reported resistance training experience did not differ between groups (p=.25, g=.61). ECCD was not different between ST (1.11±0.21 sec) and WK (1.08±0.31 sec, p=.81, g=.12). Though COND was not significant (p=.052), a large effect size (g=1.08) indicated higher COND in ST (2.76±0.55 vs 2.11±0.56 sec). ECCV was similar between groups (p=.17, g=.72). However, lower CONV was noted in ST (0.11±0.04 vs 0.18±0.04 m/s, p=.004, g=1.76). All force values were greater in ST (p<.05, g=1.64-6.43). CONCLUSION: Greater forces were seen in ST. As BM was similar, this was likely influenced by bar load. Though ECCD and ECCV were similar between groups, greater COND and lower CONV were noted in ST. As CONV can be used to predict 1RM, coaches should understand how kinematic performance differences between stronger and weaker lifters may influence 1RM performance.

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