MAXIMUM STRENGTH, RELATIVE STRENGTH, AND STRENGTH DEFICIT: RELATIONSHIPS WITH PERFORMANCE AND DIFFERENCES BETWEEN ELITE SPRINTERS AND PROFESSIONAL RUGBY UNION PLAYERS

Purpose: To test the relationships between maximum and relative strength (MS and RS), absolute and relative peak force (PF and RPF), and strength deficit (SDef), with sprint and jump performance, and to compare these mechanical variables between elite sprinters and professional rugby union players. Methods: Thirty-five male rugby union players and thirty male sprinters performed vertical jumps, 30-m sprint, and the half-squat one-repetition maximum (1RM) assessment, where these force-related parameters were collected. Pearson correlation coefficient was used to test the relationships among the variables. An independent t-test and magnitude-based inferences compared the mechanical variables between sprinters and rugby players. Results: Almost certain significant differences were observed for jump and sprint performance between the groups (P < 0.0001). Rugby union players demonstrated a likely significant higher MS (P = 0.03), but a very likely lower RS (P = 0.007) than sprinters. No significant differences were observed for PF between them. Sprinters exhibited an almost certain significant higher RPF than rugby players (P < 0.0001). Furthermore, rugby players demonstrated almost certain to likely significant higher SDef from 40 to 70% 1RM (P < 0.05) compared to sprinters. Overall, all strength-derived parameters were significantly related to functional performance. Conclusions: Elite sprinters present higher levels of RS and RPF, lower levels of SDef, and superior sprint and jump performance than professional rugby players. Relative strength-derived values (RS and RPF) and SDef are significantly associated with speed-power measures and may be used as effective and practical indicators of athletic performance.