Hamstring strain injuries (HSI) are among the most common injuries in field-based team sports with a high-speed running component. The implementation of the Nordic hamstring exercise (NHE) is a well-documented method of improving eccentric hamstring strength to mitigate the risk of HSI occurrence. Sprint training is specific to the injury mechanism and is thought to activate the hamstrings through maximal eccentric contractions. The purpose of this study was to compare the effects of sprint training and the NHE on eccentric hamstring strength and sprint performance. Twenty-eight participants (mean±SD age=16.21±1.34 years; height=1.75m±0.10m; body mass=68.5kg±12.1kg) completed an eccentric hamstring strength assessment and 40m sprint to assess acceleration and maximum speed. Participants were randomly allocated to either a NHE training or sprint training group. Two sessions per week for four-weeks of training was performed with baseline testing procedures repeated in the week following the intervention. Perceptions of soreness were recorded following the warm-up in each training session. Both the NHE (effect size=0.39, P<0.05) and sprint training (effect size=0.29, P<0.05) groups displayed significant gains in eccentric hamstring strength. The NHE group reported trivial improvements in sprint performance, whilst the sprint training group experienced a moderate improvement, specifically in maximum speed (ES=0.83 Moderate). Sprint training also produced greater perceptions of soreness than the NHE following a four-week training intervention, specifically before the start of the last session (P<0.05). These findings indicate that sprint training had a beneficial effect for both eccentric hamstring strength and sprint performance, whilst also producing greater soreness than the NHE following the final training session. It was concluded that a four-week block of maximum speed training may have both an injury prevention and performance enhancement benefit.

Freeman, BW, Talpey, SW, James, LP, Opar, DA, and Young, WB. Common high-speed running thresholds likely do not correspond to high-speed running in field sports. J Strength Cond Res 37(7): 1411–1418, 2023—The purpose of this study was to clarify what percentage of maximum speed is associated with various running gaits. Fifteen amateur field sport athletes (age = 23 ± 3.6 years) participated in a series of 55-meter running trials. The speed of each trial was determined by instructions relating to 5 previously identified gait patterns (jog, run, stride, near maximum sprint, and sprint). Each trial was filmed in slow motion (240 fps), whereas running speed was obtained using Global Positioning Systems. Contact time, stride angle, and midstance free-leg knee angle were determined from video footage. Running gaits corresponded with the following running speeds, jogging = 4.51 m·s⁻¹, 56%Vmax, running = 5.41 m·s⁻¹, 66%Vmax_, striding = 6.37 m·s⁻¹, 78%Vmax, near maximum sprinting = 7.08 m·s⁻¹, 87%Vmax, and sprinting = 8.15 m·s⁻¹, 100%Vmax. Significant (p < 0.05) increases in stride angle were observed as running speed increased. Significant (p < 0.05) decreases were observed in contact time and midstance free-leg knee angle as running speed increased. These findings suggest currently used thresholds for high-speed running (HSR) and sprinting most likely correspond with jogging and striding, which likely underestimates the true HSR demands. Therefore, a higher relative speed could be used to describe HSR and sprinting more accurately in field sports.

Background: Australian Rules Football athletes complete long preseasons, yet injuries occur frequently at early stages of the competitive season. Little is known about the high-speed running (HSR) prescription during a preseason or whether players are adequately prepared for competition. This study described absolute and relative preseason and in-season HSR demands of 2 professional Australian football teams. Hypothesis: HSR and sprinting volumes are significantly lower in elite Australian Rules football athletes during in-season compared with preseason. Study Design: Cohort study. Level of Evidence: Level 3. Methods: During the 2019 season, HSR volume was collected for 2 professional Australian football teams (n = 55). Individual maximum speeds (V_max) were captured to calculate relative running speed thresholds, as reported in 5% increments from 70%V_max to 100%V_max. Results: Weekly volume of running above 70%V_max ( P = 0.01; r = 0.56) and 80%V_max ( P = 0.01; r = 0.58) was significantly greater in the preseason than the in-season. The weekly volume completed above 90%V_max was not significantly greater in the preseason than the in-season ( P = 0.10; r = 0.22). Individual variation in the distance completed at specific percentages of V_max expressed as a coefficient of variation was reported as 51% at 71% to 80%V_max, 39% at 81% to 90%V_max, and 41% at 91% to 100%V_max. Conclusion: The volume of HSR completed by athletes is far greater in the initial 4 weeks of the preseason than in any other point in preseason or competitive phases. At the individual level, there is substantial variation in the distance covered. This supports the concept of a heavily individualized approach to high-speed prescription and monitoring. Clinical Relevance: Practitioners should carefully consider individual variation regarding sprinting volume during both preseason and in-season when prescribing and monitoring training to improve on-field performance and reduce the risk of injury.

The purpose of this study was to explore the strength and conditioning (S&C) practices within the Western Australian National Premier League men's (NPLM) and women's (NPLW) competition from an athlete's perspective. A quantitative cross-sectional survey comprising of 40 closed-ended questions was distributed to semi-professional football athletes (n = 143). Independent t-tests and chi-squared analysis were used to examine between-competition differences. NPLM athletes reported significantly longer time participating in organised football ( p = .011, d = 0.33), the NPL competition ( p = .003, d = 0.49) and earlier exposure to unsupervised ( p = .012, d = 0.38) and supervised ( p = .007, d = 0.48) resistance training than NPLW athletes. No significant differences were observed in beliefs regarding the importance of resistance, cardiorespiratory, sprint, or plyometric training, nor in perceived training obligations across the season. Training frequency during the pre-season, in-season and off-season was comparable between competitions. However, NPLM athletes were more likely to complete supervised off-season resistance training ( p = .036, ϕ _c = 0.16), cardiorespiratory training ( p = .044, ϕ _c = 0.16), and off-season physical performance testing ( p = .011, ϕ _c = 0.21). No differences were observed for recovery session participation or wellness monitoring. These findings suggest similar in-season S&C structures between semi-professional men and women in the NPL. However, there appears to be small differences between NPLM and NPLW off-season training supervision and physical performance testing. Reduced access to structured off-season support in the NPLW may contribute to developmental inequities. Practitioners and governing bodies should consider targeting strategies to improve off-season provisions within women's football.