Abstract
This study aimed to investigate the relationship between a specific isometric-strength sprint test (SIST) and unresisted maximum velocity (Vmax), sprint times across different loading conditions, and the velocity loss (Vloss) loads required to achieve each intended Vloss condition during resisted sprint training (RST) in rugby players. Additionally, the investigation examined the relationship between strength in the back-squat one-repetition maximum (1RM-SQ) as well as isometric squat (ISQT), jumps, and sprint performance variables. Twenty (n = 20) male amateur rugby players performed, on two separate occasions, a structural multiple-joint assessment of jumps, strength, and sprint performance. Interestingly, SIST revealed moderate correlations (r = 0.453 to 0.681; p < 0.05) between 1RM-SQ and ISQT. The SISTrel (relative to body mass), but not SIST, used in the present study showed moderate correlations (r = 0.508 to 0.675; p < 0.05) with the loads needed to reach 10%, 30%, and 50% of Vloss during RST. The SISTrel that measures resultant force application in a more sprint-related position explains much of the individual response of each athlete during sprinting towing a sled and can also be used to prescribe and quantify loads in the RST in a more objective and individual manner.
Highlights
Rugby union is a physically intense intermittent sport in which high-force collisions are common in match-play [1], requiring players to possess high levels of strength, power, and speed, regardlessSports 2020, 8, 34; doi:10.3390/sports8030034 www.mdpi.com/journal/sportsSports 2020, 8, 34 of playing position [2]
The results showed T30 -40BM, T30 -80BM, 1RM estimation in squat exercise (1RM-SQ), ISQTrel, sprint test (SIST), and SISTrel were not normally distributed (p < 0.05)
The aims of the present study were to explore the relationships between SIST and unresisted The aims of the present study were to explore the relationships between SIST and unresisted maximum velocity (Vmax), sprint times across different loading conditions, and the velocity loss (Vloss) loads used maximum velocity (Vmax), sprint times across different loading conditions, and the Vloss loads used during resisted sprint training (RST) in rugby players
Summary
Rugby union is a physically intense intermittent sport in which high-force collisions are common in match-play [1], requiring players to possess high levels of strength, power, and speed, regardlessSports 2020, 8, 34; doi:10.3390/sports8030034 www.mdpi.com/journal/sportsSports 2020, 8, 34 of playing position [2]. Rugby union is a physically intense intermittent sport in which high-force collisions are common in match-play [1], requiring players to possess high levels of strength, power, and speed, regardless. In the literature, resisted sprint training (RST) is gaining attention and relevance for training in sports, aiming to improve speed and power. Bourke [6] used 13% of body mass (BM) and 30 m sprints to analyse the effects of RST on speed and lower limbs strength in rugby players, and concluded that RST protocols may be useful to improve acceleration ability. According to Behrens & Simonson [7], the use of an appropriate load would be an important requirement to produce positive adaptations without drastically altering sprint mechanics
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