Keigo Kobayashi1, Michael Shepherd1, Matthew Pulscher1, Veronika Pribyslavska1, Eric Kyle O'Neal2, Gavin Brown1, Zadie Coats1 and Eric Scudamore1

1Arkansas State University, Jonesboro, AR

2University of North Alabama, Florence, AL

Abstract. External loading during daily living (ELDL) consists of wearing a weighted vest during outside of training session activities and may improve anaerobic performance. ELDL programming typically consists of wearing 10-15% of individual body mass 8 hrs/day, 4 days/week, for three weeks. No investigations have objectively assessed compliance with weight vest protocols, or explored the possibility of dose-response relationships between ELDL and anaerobic performance. PURPOSE: Explore associations between ELDL total wear time and percentage change on anaerobic performance tasks in rugby athletes. METHODS: Seven D1-A rugby athletes completed three weeks of ELDL with loads of 10%, 12.5%, and 15% of their respective body weight. Loads were not worn during training. Participants were instructed to wear loads at least 8 hrs/day, 4 days/week, for three weeks. Tri-axial accelerometers were placed in the center pocket on the front of each weight vest to assess wear time. Wear time validation parameters were set to 30 minutes non-activity threshold. Baseline and post-ELDL assessments were identical and consisted of a single counter movement jump (CMJ), four continuous jumps (4CJ), 40 m sprint (SP), 15 yd sled push (SLD), and were reassessed after three weeks of ELDL. Percentage change from post-ELDL and baseline were calculated for all performance variables. Pearson correlation analyses were used to examine relationships between wear time and change in each performance variable. RESULTS: Average wear time across the 3-week ELDL period was 73.00 ± 33.77 hrs. No relationship was found between CMJ height (6.20 ± 25.45%; r = -0.53, p = 0.11). Change in 4CJ height decreased (-6.25 ± 11.01%; r = 0.24, p = 0.30), but ground contact time (-11.41 ± 15.28%, r = 0.003, p = 0.50), and explosive leg power factor (ELPF) (11.26 ± 17.16%, r = 0.01, p = 0.49) were not related to wear time. Wear time was not correlated (r = -0.32, p = 0.24) with change in SP (-1.45 ± 3.01%) or SLD (2.93 ± 5.34%; r = -0.45, p = 0.15). CONCLUSION: No dose-response relationship between ELDL wear time and change in performance was observed. Subjective review of scatter plot data suggest that a dose-response relationship may be identifiable with a larger sample size.

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