The effects of lower-limb wearable resistance on sprint performance in high school American football athletes: A nine-week training study

Abstract

Time constraints often result in the challenge to fit desired programming into training time allotments. Wearable resistance (WR) may be an option to optimise the training content in function of constrained training time. The purpose of this study was to determine the effects of a lower-limb WR sprint running training intervention on athlete speed capabilities following a nine-week off-season, low volume training period within a sample of American football high school athletes. Nineteen athletes completed pre- and post-intervention testing of two maximal effort 30 m sprints. Horizontal force-velocity mechanical profiling variables, sprint times, and maximal velocity were calculated from sprint running velocity data collected by a radar device. The athletes completed seventeen dedicated sprint training sessions during the off-season. The intervention (WR) group completed the sessions with 1% body mass load attached to the shanks (i.e. 0.50% body mass load on each limb). The control group completed the same training sessions unloaded. Post-intervention, no statistically significant between group differences were observed ( p > 0.05). However, athletes in both groups experienced increases in velocity measures following the sprint training. The greater adjusted mean theoretical maximal velocity scores ( p > 0.05; ES = 0.30) found for the WR group compared to the control group at post-intervention may suggest that WR amplifies the nuances of the training protocol itself. Coaches can consider using lower-limb WR training to increase in-session workloads during periods of low volume training but more research is needed to better understand to what extent WR training might provide an added value to optimise both the training content and planning, as well as the athlete’s training response in order to improve sprint running performance.

Hip Torque Is a Mechanistic Link Between Sprint Acceleration and Maximum Velocity Performance: A Theoretical Perspective

“…Several external factors may cause measured values for a 0 to differ from our estimated limit values. Lower measured values of a 0 may occur if there is insufficient friction between the ground and foot, if the athlete starts from a standing two-point stance (Slawinski et al, 2017b ), or when testing developmental athletes (Cahill et al, 2020 ; Feser et al, 2021 ) who may have less experience in starting technique. Additionally, athletes with higher estimated a 0 capability may control the initial horizontal acceleration to optimize the projection angle of the COM (Kugler and Janshen, 2010 ), also resulting in lower measured values of a 0 .…”

Effects of wearable resistance load placement on neuromuscular activity and stride kinematics: A preliminary study

“…While the study findings may not have been conclusive in identifying the stride characteristics and EMG activity of using lower-limb WR, the results from previous lower-limb loaded WR studies imply that using WR may allow coaches to induce a training overload explicit to sport-specific movement mechanics. [ 5 – 7 ] Furthermore, lower-limb WR may be used to increase acute training workloads, but further research is required with larger sample sizes to understand the locomotor and neuromuscular effects of WR training in more detail. [ 6 , 7 ] Future research may also aim to increase the WR load or increase exposure times to the load, to investigate potential performance benefits of WR training.…”

“…[ 1 , 4 ] Additionally, investigations have explored the potential performance benefits of using WR for team sports. [ 5 – 7 ] One study investigating the use of calf-loaded WR during warm-ups for elite footballers reported improvements in maximal horizontal (e.g. 10- and 20m sprints) but not vertical (e.g.…”

“…[ 6 ] Furthermore, WR training increased acute training load for high school American footballers loaded with 1% BM on the calves. [ 7 ]…”

Short-Term Influence Analysis of Different Instep Weights on 50 Meters Speed and Running Time

“…8 Extra weights inclusion during specific training exercise report improvements in biomechanical parameters and performance values. 9 Developing strength and resistance gains in specific running movements could cause better training-performance transference, 3,10 improvements also recorded in other sports as tennis, 8 based on performance changes including forces' direction (lateral and horizontal), unilateral propulsion, full range and speed performance, cyclic movements, and multi-planar field. 3 Several mechanical determinants that are overloaded by lower-limb wearable resistance may be influenced over time to produce positive speed adaptations.…”