BACKGROUND: Elastic bands are used as a training modality to help improve different aspects of an individual’s ability to sprint. It is important to ensure that the specificity of the exercise is understood so that proper use and application of elastic bands training can be applied. The purpose of this study was to compare the ankle, knee and hip joint kinematics during forward and backward shuttle sprints with the addition of resistance or assistance bands compared to without elastic bands.METHODS: Eight college and high school aged (19.9±3.5 yrs), competitively active female soccer players completed forward and backward 10m shuttle sprints while elastic bands provided either assistance or resistance. Additional forward/backward sprints were completed with just body weight (BW). The order of sprint direction and load were randomized between participants. Following a familiarization period, participants were outfitted with electromagnetic receivers (feet, shanks, thighs, pelvis) and two synchronized foot switches. Two sets of 8 sprints under each condition were completed. At the sprint midpoint (5m), dominant limb ankle, knee, and hip angular distance (AD) during stance phase were computed and statistically analyzed with a joint by condition by direction analysis of variance. RESULTS: With a statistically significant 3-way interaction (P<.001), separate joint by condition interaction contrasts for each direction were conducted. For forwards sprints, resistance prompted significant reductions in knee AD compared to BW (P=.001, d=3.6) and assistance (P=.013, d=2.2) whereas assistance (P=.012, d=1.5) and resistance (P=.001, d=2.9) caused a reduction in hip AD compared to BW; there were no significance changes in ankle AD (P>.115). For backwards sprints, load did not significantly impact AD (interaction: P=.382; main effect: P=.141). Post hoc of a significant joint main effect (P<.001) revealed knee AD to be significantly greater than ankle (P=.003, d=1.3) and hip (P<.001, d=1.9); additionally, ankle AD was significantly greater than hip (P<.001, d=2.8). CONCLUSION: These results show that the AD changes may prompt a change in exercise specificity when using elastic bands to train in the forwards direction. However, based on the lack of statistically significant results, the use of elastic bands to train in the backwards direction does not seem to have an impact on the specificity of the exercise.

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