18Background: With distance running gaining popularity, there is a concurrent increase in

No abstract

Gait retraining is an effective intervention to reduce KAM during walking and to improve the symptoms of patients with early knee osteoarthritis in short term.

Real‐time biofeedback gait retraining has been reported to be an effective intervention to lower the impact loading during gait. While many of the previous gait retraining studies have utilized a laboratory‐based setup, some studies used accelerometers affixed at the distal tibia to allow training outside the laboratory environment. However, many commercial sensors for gait modification are shoe‐mounted. Hence, this study sought to compare impact loading parameters measured by shoe‐mounted and tibia sensors in participants before and after a course of walking or running retraining using signal source from the shoe‐mounted sensors. We also compared the correlations between peak positive acceleration measured at shoe (PPAS) and tibia (PPAT) and vertical loading rates, as these loading rates have been related to injury. Twenty‐four and 14 participants underwent a 2‐week visual biofeedback walking and running retraining, respectively. Participants in the walking retraining group experienced lower PPAS following the intervention (P < 0.005). However, they demonstrated no change in PPAT (P = 0.409) nor vertical loading rates (P > 0.098) following the walking retraining. In contrast, participants in the running retraining group experienced a reduction in the PPAT (P = 0.001) and vertical loading rates (P < 0.013) after running retraining. PPAS values were four times that of PPAT for both walking and running suggesting an uncoupling of the shoe with tibia. As such, PPAS was not correlated with vertical loading rates for either walking or running, while significant correlations between PPAT and vertical loading rates were noted. The present study suggests potential limitations of the existing commercial shoe‐mounted sensors.

Gait retraining using visual biofeedback has been reported to reduce impact loading in runners. However, most of the previous studies did not adequately examine the level of motor learning after training, as the modified gait pattern was not tested in a dual-task condition. Hence, this study sought to compare the landing peak positive acceleration (PPA) and vertical loading rates during distracted running before and after gait retraining. Sixteen recreational runners underwent a two-week visual biofeedback gait retraining program for impact loading reduction, with feedback on the PPA measured at heel. In the evaluation of PPA and vertical loading rates before and after the retraining, the participants performed a cognitive and verbal counting task while running. Repeated measures ANOVA indicated a significant interaction between feedback and training on PPA (F = 4.642; P = 0.048) but not vertical loading rates (F > 1.953; P > 0.067). Pairwise comparisons indicated a significantly lower PPA and vertical loading rates after gait retraining (P < 0.007; Cohen's d > 0.68). Visual feedback after gait retraining reduced PPA and vertical loading rates during distracted running (P < 0.033; Cohen's d > 0.36). Gait retraining is effective in lowering impact loading even when the runners are distracted. In dual-task situation, visual biofeedback provided beneficial influence on kinetics control after gait retraining.

Visual feedback gait retraining has been reported to successfully reduce impact loading in runners, even when the runners were distracted. However, auditory feedback is more feasible in real life application. Hence, this study compared the peak positive acceleration (PPA), vertical average (VALR) and instantaneous (VILR) loading rate during distracted running before and after a course of auditory feedback gait retraining in 16 runners. The runners were asked to land with softer footfalls with and without auditory feedback. Low or high sound pitch was generated according to the impact of particular footfall, when compared with the preset target. Runners then received a course of auditory gait retraining, and after the gait retraining, runners completed a reassessment. Runners before gait retraining exhibited lower PPA, VALR and VILR with augmented auditory feedback (p<0.049). We found a reduction in PPA, VALR and VILR after gait retraining, regardless of the presence of feedback (p<0.018). However, runners after gait retraining did not demonstrate further reduction in PPA and VALR with auditory feedback (p>0.104). A small effect of auditory feedback on VILR in runners after gait retraining was observed (p=0.032). Real time auditory feedback gait retraining is effective in impact loading reduction, even when the runners were distracted.

Barefoot running has been proposed to reduce vertical loading rates, which is a risk factor of running injuries. Most of the previous studies evaluated runners on level surfaces. This study examined the effect of surface inclination on vertical loading rates and landing pattern during the first attempt of barefoot running among habitual shod runners. Twenty habitual shod runners were asked to run on treadmill at 8.0 km/h at three inclination angles (0°; +10°; −10°) with and without their usual running shoes. Vertical average rate (VALR) and instantaneous loading rate (VILR) were obtained by established methods. Landing pattern was decided using high-speed camera. VALR and VILR in shod condition were significantly higher (p < 0.001) in declined than in level or inclined treadmill running, but not in barefoot condition (p > 0.382). There was no difference (p > 0.413) in the landing pattern among all surface inclinations. Only one runner demonstrated complete transition to non-heel strike landing in all slope conditions. Reducing heel strike ratio in barefoot running did not ensure a decrease in loading rates (p > 0.15). Conversely, non-heel strike landing, regardless of footwear condition, would result in a softer landing (p < 0.011).

Facilitatory KT promotes maximal grip strength only among regular KT users, but its effect is trivial. Interestingly, such effect is not related to any electrophysiological change in the KT applying muscle, which may indicate an indirect working mechanism leading to the increased grip strength.