Effects of deceptive footwear condition on subjective comfort and running biomechanics

Comfort is a major criterion for footwear selection. Previous studies have suggested that physical properties were not enough to predict comfort and psychological factors could also affect the perception. To understand comfort, this study examined the effect of controlled shoe description and price cue on the perception of comfort. Furthermore, this study also examined the running biomechanics in response to footwear conditions of differing comfort. Fifteen runners completed treadmill running tests in two conditions: Shoe A and Shoe B. The same pair of neutral running shoes was used in both conditions, yet, Shoe B was described to be the “latest model designed to maximize comfort” and more expensive than Shoe A. Comfort assessment was conducted after the running trial of each condition. Participants reported significantly greater comfort in Shoe B than Shoe A (p=0.011, Cohen’s d=0.70). There were no significant differences found among the temporal-spatial parameters (p>0.916) and the vertical loading rates (p>0.161) when comparing the more and less comfortable conditions. In conclusion, runners exhibited a biased perception of footwear comfort when presented with different shoe description and price information. However, such a difference in perceived comfort alone is not likely to affect running biomechanics

Gait Retraining for the Reduction of Injury Occurrence in Novice Distance Runners: 1-Year Follow-up of a Randomized Controlled Trial

Background: The increasing popularity of distance running has been accompanied by an increase in running-related injuries, such that up to 85% of novice runners incur an injury in a given year. Previous studies have used a gait retraining program to successfully lower impact loading, which has been associated with many running ailments. However, softer footfalls may not necessarily prevent running injury. Purpose: To examine vertical loading rates before and after a gait retraining program and assess the effectiveness of the program in reducing the occurrence of running-related injury across a 12-month observation period. Study Design: Randomized controlled trial; Level of evidence, 1. Methods: A total of 320 novice runners from the local running club completed this study. All the participants underwent a baseline running biomechanics evaluation on an instrumented treadmill with their usual running shoes at 8 and 12 km/h. Participants were then randomly assigned to either the gait retraining group or the control group. In the gait retraining group (n = 166), participants received 2 weeks of gait retraining with real-time visual feedback. In the control group (n = 154), participants received treadmill running exercise but without visual feedback on their performance. The training time was identical between the 2 groups. Participants’ running mechanics were reassessed after the training, and their 12-month posttraining injury profiles were tracked by use of an online surveillance platform. Results: A significant reduction was found in the vertical loading rates at both testing speeds in the gait retraining group (P 0.99), whereas the loading rates were either similar or slightly increased in the control group after training (P = .001 to 0.461, Cohen’s d = 0.03 to −0.14). At 12-month follow-up, the occurrence of running-related musculoskeletal injury was 16% and 38% in the gait retraining and control groups, respectively. The hazard ratio between gait retraining and control groups was 0.38 (95% CI, 0.25-0.59), indicating a 62% lower injury risk in gait-retrained runners compared with controls. Conclusion: A 2-week gait retraining program is effective in lowering impact loading in novice runners. More important, the occurrence of injury is 62% lower after 2 weeks of running gait modification. Registration: HKUCTR-1996 (University of Hong Kong Clinical Trials Registry)

Impact loading during distracted running before and after auditory 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 (p0.104). 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

Measurement agreement between a newly developed sensing insole and traditional laboratory-based method for footstrike pattern detection in runners

This study introduced a novel but simple method to continuously measure footstrike patterns in runners using inexpensive force sensors. Two force sensing resistors were firmly affixed at the heel and second toe of both insoles to collect the time signal of foot contact. A total of 109 healthy young adults (42 males and 67 females) were recruited in this study. They ran on an instrumented treadmill at 0˚, +10˚, and -10˚ inclinations and attempted rearfoot, midfoot, and forefoot landings using real time visual biofeedback. Intra-step strike index and onset time difference between two force sensors were measured and analyzed with univariate linear regression. We analyzed 25,655 footfalls and found that onset time difference between two sensors explained 80–84% of variation in the prediction model of strike index (R-squared = 0.799–0.836, p<0.001). However, the time windows to detect footstrike patterns on different surface inclinations were not consistent. These findings may allow laboratory-based gait retraining to be implemented in natural running environments to aid in both injury prevention and performance enhancement

Decoding auditory and tactile attention for use in an EEG-based brain-computer interface

International audienceBrain-computer interface (BCI) systems offer a non-verbal and covert way for humans to interact with a machine. They are designed to interpret a user's brain state that can be translated into action or for other communication purposes. This study investigates the feasibility of developing a hands-and eyes-free BCI system based on auditory and tactile attention. Users were presented with multiple simultaneous streams of auditory or tactile stimuli, and were directed to detect a pattern in one particular stream. We applied a linear classifier to decode the stream-tracking attention from the EEG signal. The results showed that the proposed BCI system could capture attention from most study participants using multisensory inputs, and showed potential in transfer learning across multiple sessions

Facilitatory and inhibitory effects of Kinesio tape : fact or fad?

Objectives: Kinesio tape (KT) is a commonly used intervention in sports. It claims to be able to alter the muscle activity, in terms of both facilitation and inhibition, by certain application methods. This study compared the neuromuscular activity of the wrist extensor muscles and maximal grip strength with facilitatory, inhibitory KT, and tapeless condition in healthy adults who were ignorant about KT. Potential placebo effects were eliminated by deception. Design: Randomized deceptive trial. Methods: 33 participants performed maximal grip assessment in a randomly assigned order of three taping conditions: true facilitatory KT, inhibitory KT, and no tape. The participants were blindfolded during the evaluation. Under the pretense of applying a series of adhesive muscle sensors, KT was applied to their wrist extensor muscles of the dominant forearm in the first two conditions. Within-subject comparisons of normalized root mean square of the wrist extensors electromyographic activity and maximal grip strength were conducted across three taping conditions. Results: 31 out of 33 enlisted participants were confirmed to be ignorant about KT. No significant differences were found in the maximum grip strength (p = 0.394), electromyographic activity (p = 0.276), and self-perceived performance (p = 0.825) between facilitatory KT, inhibitory KT, and tapeless conditions. Conclusions: Neither facilitatory nor inhibitory effects were observed between different application techniques of KT in healthy participants. Clinically, alternative method should be used for muscle activity modulation

Cyclists with patellofemoral pain do not demonstrate altered hip and knee kinematics

Background: Cycling is a popular sport but overuse injury, especially patellofemoral pain, is a very common musculoskeletal disorder among cyclists. Faulty kinematics at the hip and knee joints in runners with patellofemoral pain has been extensively investigated. Previous studies reported that a greater peak hip adduction, femoral internal rotation, knee adduction, and knee tibial internal rotation are associated with the development of patellofemoral pain in this cohort. Relatively, little work has been done to examine the relationship between patellofemoral pain and the lower extremities kinematics in cyclists. Purpose: This study examined the difference between the 3-dimensional kinematics on the coronal and transverse plane of the hip and knee joints between cyclists with and without patellofemoral pain. Methods: Fourteen cyclists participated in the study. Seven of them were patients with patellofemoral pain with proper diagnosis. Another seven cyclists were healthy characteristic-matched controls. During the experiment, all the subjects rode with their usual bike mounting on a trainer at standardized cadence, speed, and power. Motion analysis system was used to capture the three-dimensional movements of the affected lower limbs and the side-matched limbs in the experimental and control group respectively. Mann Whitney U tests were used to test the dependent variables between two groups. Results: In the coronal plane movement, no statistical significance was found in peak hip and knee adduction between the cyclists with and without PFP (p ranged from 0.259 to 0.456). In the transverse plane movement, we also failed to detect any difference in peak hip and knee internal rotation between two groups (p ranged from 0.259 to 0.966). Conclusion(s): Cyclists with patellofemoral pain did not demonstrate any kinematics difference at hip and knee joints when compared with healthy cyclists. Our findings indicated that the theory explaining the development of PFP during weight bearing exercises e.g. running, may not be applicable to cycling

Can runners maintain a newly learned gait pattern outside a laboratory environment following gait retraining?

Background: Previous peak tibial shock gait retraining programs, which were usually conducted on a treadmill, were reported to be effective on impact loading reduction in runners. However, whether the trained runners can translate the training effect at different running modes (treadmill/overground), or running slopes (uphill/ downhill), remains unknown. Research question: Is the training effect from a treadmill-based gait retraining translatable to unconstrained running conditions, including overground and uphill/downhill running? Methods: The peak tibial shock was measured during treadmill/overground running, as well as level/uphill/ downhill running before and after a course of treadmill-based gait retraining. The 8-session training aimed to soften footfalls using real-time biofeedback of tibial shock data. Repeated measures ANOVA was used to examine the effect of training, running mode, and running slope, on a group level. Reliable change index of each participant was used to assess the individual response to the training protocol used in this study. Results: Eighty percent of the participants were responsive to the gait retraining and managed to reduce their peak tibial shock following training. They managed to translate the training effect to treadmill slope running (Level: p < 0.05, Cohen’s d = 1.65; Uphill: p = 0.001, Cohen’s d = 0.91; Downhill: p < 0.05; Cohen’s d = 1.29) and overground level running (p = 0.014, Cohen’s d = 0.85). However, their peak tibial shock were not reduced during overground slope running (Uphill: p = 0.054; Cohen’s d = 0.62; Downhill p = 0.12; Cohen’s d = 0.48). Significance: Our findings indicated that a newly learned gait pattern may not fully translate to running outside of the laboratory environment

Transfer of the learning effect in outdoor conditions with varied surface inclinations upon completion of an indoor gait retraining program

Rational & Objective Running retraining using kinetic biofeedback (e.g., tibial shock) has been shown to be effective in impact loading control and injury prevention. Previous training program was usually conducted indoor to enable continuous feedback of peak tibial shock. However, it is not known if the training could benefit running in outdoor conditions across various surface inclinations (e.g., uphill or downhill). This study aimed to compare the reduction in peak tibial shock following running retraining during indoor and outdoor running across varying surface inclinations. Methods Fourteen runners underwent a running retraining program as described by Crowell and Davis in 2011. Before and after the program, participants were asked to perform indoor treadmill running and outdoor overground running at three inclination surfaces (level, 10% uphill and - 10% downhill). During all the six conditions, their peak acceleration from right distal tibia were measured using wireless accelerometers. Results The effect of training depended on running environment (F(1,13) = 11.179, p = 0.005) as well as surface inclinations (F(2,13) = 4.322, p = 0.024). During indoor running, participants managed to reduce the peak tibial shock during level and downhill running (p 0.137, Cohen’s d = 0.32-0.47). Conclusions The learning effect of the current running gait retraining program may not transfer to a reduced peak tibial shock during various inclination surfaces and outdoor running conditions