@phdthesis{8732965,
  abstract     = {{Running is a gross-motor skill and a popular physical activity, though it comes with a risk of injury. Gait retraining is performed with the intent on managing the risk of running injury. The peak tibial acceleration may be linked with running injuries and is suitable as input for biofeedback. So far, retraining programs with the use of biofeedback on peak tibial acceleration have been bound to a treadmill. Therefore, the objective of this doctoral thesis was to evaluate the effectiveness of a novel music-based biofeedback system on peak tibial acceleration in the context of gait retraining in a training environment. This system is wearable and has lightweight sensors to attach to the lower leg. The sensor first records the tibial acceleration. Then, a processing unit detects the acceleration spike for direct auditory biofeedback. 
Studies 1 to 5 covered the measurement of peak tibial accelerations, the design of the music-based feedback, and the effectiveness evaluation of the biofeedback system for impact reduction in a training center. In study 1 the peak tibial acceleration of a group of distance runners was reliable in the same test and repeatable in a re-test. The peak tibial accelerations increased with running speed and were correlated with the maximum vertical loading rate of the ground reaction force, which is an impact characteristic derived in the biomechanics laboratory. The developed peak detection algorithm identified the peak tibial acceleration in real-time. The music-based feedback was developed in study 2. The music was superimposed with perceptible pink noise. The noise intensity could be linked to a biological parameter such as the peak acceleration tibial. The tempo of the music synchronized with the cadence of the runner to motivate the runner and allowed for a user-induced change in cadence in response to the biofeedback. Studies 3 to 5 examined the effectiveness of music-based biofeedback on the peak tibial peak in a training environment. We demonstrated that smaller peak values are achievable with the aid of the validated biofeedback system. In study 3, ten runners with high peak tibial acceleration were subjected to biofeedback on the momentary peak tibial acceleration. The group was able to reduce their peak tibial acceleration by 27% or 3 g in the biofeedback condition. Study 4 evaluated the initial learning effect within a single session at ~11.5 km/h. The main change in peak acceleration occurred after approximately 8 minutes of biofeedback. However, there was substantial between-subject variation in time which ranged from 4 to 1329 gait cycles. Study 5 confirmed the effectiveness of the biofeedback in a quasi-randomized study with control group. The experimental group received the biofeedback in a 3-week retraining program comprising of biofeedback faded in time. The control group received tempo-synchronized music as placebo. A running speed of approximately 10 km/h was maintained session after session via speed feedback. All runners completed the running program consisting of 6 sessions. The peak acceleration decreased by 26% or 3 g in the experimental group. The smaller peak values in studies 3-5 must have resulted from a movement alteration, although there was no significant change in running cadence at the group level. 
Studies 6 to 9 give insight into possible strategies for low(er) peak tibial acceleration in level running. In study 6, we discovered that peak tibial accelerations depend on the manner of heel striking. Specifically, a more pronounced heel landing was correlated with smaller axial (1D) and resultant (3D) peak tibial accelerations. The multicenter results of study 7 showed greater resultant peak acceleration in non-rearfoot strikes compared with heel strikes. This greater acceleration was due to an abrupt horizontal deceleration of the lower leg. In study 8, we described and compared the running mechanics of a successful long-distance runner with low (impact) load and a high load capacity. A pronounced heel strike in conjunction with long stance and short flight phases characterized a low-impact runner who successfully completed 100 marathons in 100 days. Study 9 documented adaptations post-biofeedback in a lab center. There was no clear relationship between the changes in peak tibial acceleration and in running cadence, which confirmed the results of the data captured in the training center. Casuistry showed visually detectable changes in the curve of the vertical ground reaction force. A runner with high peak tibial acceleration peaks changed to a more pronounced rearfoot strike or changed to a non-rearfoot strike pattern to reduce the axial peak tibial acceleration. These results suggest the existence of different distal strategies for impact reduction elicited by biofeedback. 
Our experiments opened the possibility of impact reduction with the use real-time auditory biofeedback that is perceptible and motivating. Two motor strategies were discovered to run with less peak tibial acceleration. We hope these findings offer encouragement for runners, coaches and clinicians who wish to target a form of low(er) impact running. The biofeedback system effectively modified the running form and has great ecological value due to the portable hardware and energy source for outdoor usage. User-oriented biofeedback systems should become available for the consumer and the patient if proven useful for respectively injury reduction and injury management. Overall, this doctoral thesis contributed to a better understanding of impact severity in distance running and its reduction in a gait retraining context with the use of real-time music-based biofeedback.}},
  author       = {{Van den Berghe, Pieter}},
  keywords     = {{biomechanics,running,injury,impact,sonification,music,sport,sports,movement analysis,force,kinetics,kinematics}},
  language     = {{eng}},
  pages        = {{IX, 296}},
  publisher    = {{Ghent University. Faculty of Medicine and Health Sciences}},
  school       = {{Ghent University}},
  title        = {{Motor retraining by real-time sonic feedback : understanding strategies of low impact running}},
  url          = {{https://www.ugent.be/ge/bsw/en/research/biomechanics/projects#motor-retraining-by-real-time-sonic-feedback---understanding-strategies-of-low-impact-running}},
  year         = {{2021}},
}