Researchers from the University of Salford have recently had an article published ahead of print in the Journal of Strength and Conditioning Research. The study investigated the relationships between maximal lower body strength, sprint and jump performance in youth soccer players.
Sprint performance is important in many sports, including football, and can vary dependent upon standard of play (youth, semi-professional, professional, and elite). Elite soccer players spend approximately 11% of the game sprinting, which equates to a 10-15m sprint every 90 seconds (Withers et al., 1982; Bangsbo, 2006). In many sports, low loads, such as kicking and throwing, and high loads, such as body weight during sprints and jumps, must be accelerated (Verheijen, 1998; Reilly, 2006). Athletes must possess sufficient strength to overcome or accelerate body mass. McBride et al., (2009) found a small-to-moderate relationship between absolute strength in the back squat and sprint performance, whereas Wisloff et al., (2004) found a strong correlation (r=0.94) between 1RM squat performance and 10m sprint in professional soccer players.
The testing protocol included 34 well trained (≥3 x week for ≥2 years) male youth soccer players. Tests selected were 1RM back squat, 5-, and 20-m sprint, squat jump (SJ), and countermovement jump (CMJ). It is important to note that testing was conducted mid-season, so all players were training full time. Therefore, other skills, tactical, speed, and conditioning being trained concurrently could have affected the results of the study. This is in contrast to previous research, where subjects are usually recreationally trained, or testing occurs during the off-season. The athletes were tested to positive failure with a 5RM, this was then equated to predict 1RM back squat. The authors acknowledged the potential problems in using regression equations, indicating a lowered risk of musculoskeletal injury for athletes that are unaccustomed to training with maximal loads.
Results showed moderate-strong relationships (r=0.52-0.67) between strength and sprint times. In addition strength showed strong relationships (r=0.62-0.76) with jump performance. Absolute strength showed strongest correlations with 5m sprint times (r=0.60), SJ height (r=0.76), and CMJ height (r=0.76), whereas relative strength (1RM/BM) showed strongest correlation with 20m sprint times (r=0.67).
The results of the study illustrate the importance of developing high levels of strength in order to enhance sprint and jump performance in youth soccer athletes, with stronger athletes tending to demonstrate the best sprint and jump performances and the weaker athletes demonstrating the worst sprint and jump performances.
The authors acknowledged that a strong correlation does not imply cause and effect. Strength training should be improved as part of a periodized programme, ensuring that technical proficiency in sprint mechanics and exercise technique (resistance training lifts) is not neglected.
Comfort, P., Stewart, A., Bloom, L., and Clarkson, B. (2013). Relationships between strength, sprint and jump performance in well trained youth soccer players. Journal of Strength and Conditioning Research, DOI: 10.1519/JSC.0b.13e318291b8c7