7% (p = 0.0014) in peak medial GRF ( Table 2). Similar trends were seen with a large, statistically significant decrease in lateral impulse (44%, p < 0.0001) and a less drastic decrease in medial impulse (2.4%, p = 0.0474). Vertical impulse was also significantly decreased between shod and instructed BF running (6.6%, p < 0.0001). SR increased by an average of 10 steps/min (6.0%) during BF running

compared to shod. This was complemented by a 5.5% decrease in step length for the BF condition. However, as step rate increased there was a decrease in vertical impulse (r = −0.881, p < 0.0001) and low stiffness, kl (r = 0.797, p < 0.0001). We hypothesized that habitually shod runners who demonstrated an impact transient would reduce loading and vertical stiffness when running BF following verbal and visual feedback to encourage an FFS pattern. Previous studies demonstrated an increase in loading rates when BF runners persisted with an RFS pattern.3, Ceritinib 19, 24 and 25 The important distinction in this study was that we did not allow runners to adapt to the BF condition independently. All eight variables of interest (VILS, VALR, VILR, PMF, PLF, V-Imp, M-Imp, L-Imp) were significantly reduced in this cohort of injured runners during the

instructed BF run compared to the shod. SKI-606 cell line The majority of patients who had impact transients during the shod run (384 of 392 steps) were able to eliminate or reduce the number of these during the instructed BF run (99 of 392 steps; Table 1). This is likely related to the fact that 96% of patients were able to convert to an FFS pattern while running BF given feedback and verbal instruction. These results are significant since previous studies suggest that novice BF runners may fail to adopt an FFS pattern independently.3 and 16 We introduced a robust method to classify the presence or absence of an impact transient. This differs from many studies which use the presence of an impact “peak” to signify that an impact transient exists.16 The VIP is a local maximum that occurs prior to the overall peak, defined by de Wit as “the first vertical impact force peak”. The presence or absence of this VIP influences the

manner in which other variables, such as the loading rate and stiffness are Olopatadine computed. In steps where no impact “peak” was detected, our model determined that a high and low stiffness was required to adequately approximate VGRF (Table 1), and thus an impact “transient” existed. Despite lacking an impact “peak”, these curves often exhibited higher stiffness during initial loading and higher loading rates of VGRF than steps fit with the simple model. Had we only searched for local maxima, or impact peaks, we would have underestimated the number of steps with an impact transient by 34 and 58 steps for the shod and instructed BF conditions, respectively. This would have resulted in an underestimate of VILS for these steps by 26% in the shod condition (25.0 vs. 38.2 kN/m) and 35% in the BF condition (25.7 vs. 34.7 kN/m).