Fig. 4.
Reduced energy expenditure during exotendon running. (A) On day 1, runners initially showed no change in energy expenditure (trial 1), yet showed reductions after running with the exotendon for 15–20 min (trial 2). Runners retained these savings across days (trial 3). After a total of 35–40 min of experience with the exotendon across both days, the greatest reductions in energy expenditure were evident (trial 4), with all runners (n=12) showing improved economy and average savings of 6.4±2.8%. Error bars represent 1 s.d. Asterisks indicate statistical significance after Holm–Šidák correction with confidence level α=0.05. (B) By the final trial, participants took shorter, faster strides with the exotendon, increasing stride frequency by an average of 8% above that measured during natural running (P=1.1×10−5, two-tailed paired t-test, n=12).