Music-based biofeedback to reduce tibial shock in over-ground running: a proof-of-concept study

Methods to reduce impact in distance runners have been proposed based on real-time auditory feedback of tibial acceleration. These methods were developed using treadmill running. In this study, we extend these methods to a more natural environment with a proof-of-concept. We selected ten runners with high tibial shock. They used a music-based biofeedback system with headphones in a running session on an athletic track. The feedback consisted of music superimposed with noise coupled to tibial shock. The music was automatically synchronized to the running cadence. The level of noise could be reduced by reducing the momentary level of tibial shock, thereby providing a more pleasant listening experience. The running speed was controlled between the condition without biofeedback and the condition of biofeedback. The results show that tibial shock decreased by 27% or 2.96 g without guided instructions on gait modification in the biofeedback condition. The reduction in tibial shock did not result in a clear increase in the running cadence. The results indicate that a wearable biofeedback system aids in shock reduction during over-ground running. This paves the way to evaluate and retrain runners in over-ground running programs that target running with less impact through instantaneous auditory feedback on tibial shock.

Midfoot Strikers Are Different from Forefoot Strikers, but Similar to Rearfoot Strikers

Category: Sports Introduction/Purpose: Rearfoot strike (RFS) patterns have an impact transient that is associated with running injuries. These transients are not present in FFS patterns. Midfoot strike (MFS) runners are often grouped with FFS runners in studies as they are both non-heel strike patterns and assumed to be similar. However, this has not been tested. Tibial shock (TS) provides a measure of impacts and can be easily assessed in the field. Therefore, the purpose of this study was to compare TS among differing footstrike patterns measured during a marathon race. We hypothesized that MFS would have greater impacts than FFS, but lower than RFS. We also aimed to examine how impacts vary across speeds. We hypothesized that impacts would increase with speed similarly in RFS, MFS and FFS. Methods: 224 healthy runners (119 M, 105 F; 44.1±10.8 yrs) running the 2016 Boston marathon volunteered for the study. Prior to the race, participants ran on a treadmill to determine their habitual footstrike pattern (169 RFS, 32 MFS, 23 FFS). On race day, they ran the course wearing an accelerometer strapped onto their right medial ankle. For this part of the study, the average of the peak TS recorded between the 5 km and 10 km point of the race. This region was used as it had a flat gradient. The peak TS was recorded for each footstrike and averaged over the 5 km distance. This value was compared between the three footstrike patterns using an ANOVA (p<0.05). A regression analysis was used to determine the interaction of FSP and speed for each FSP using individual marathon runner data points. An ANOVA (p<0.05) was used to assess significance of the regression. Results: TS in FFS runners was significantly less than in MFS (P=0.01) and RFS (P=0.01) runners. (Figure 1, top panel). There was no difference between RFS and MFS (P=0.49). When examining the relationship between TS and speed, a significant positive correlation was noted for RFS (p<0.00). and MFS (p=0.02), but not for FFS (p=0.82) (Figure 1, bottom panel). Conclusion: In contrast to common belief, MFS runners exhibit impacts that are like RFS runners, and both are higher than FFS runners. This suggests that MFS runners should be grouped with RFS runners, and not FFS runners, when assessing impacts. In addition, both RFS and MFS runners exhibited greater impacts as speed increased. However, FFS runners appear to be able to maintain lower impacts at faster speeds. This may be due to greater calf activation, mitigating the effect of increasing speed on impacts. This may offer protection from impact-related injuries in FFS runners.

Do running speed and shoe cushioning influence impact loading and tibial shock in basketball players?

Background Tibial stress fracture (TSF) is a common injury in basketball players. This condition has been associated with high tibial shock and impact loading, which can be affected by running speed, footwear condition, and footstrike pattern. However, these relationships were established in runners but not in basketball players, with very little research done on impact loading and speed. Hence, this study compared tibial shock, impact loading, and foot strike pattern in basketball players running at different speeds with different shoe cushioning properties/performances. Methods Eighteen male collegiate basketball players performed straight running trials with different shoe cushioning (regular-, better-, and best-cushioning) and running speed conditions (3.0 m/s vs. 6.0 m/s) on a flat instrumented runway. Tri-axial accelerometer, force plate and motion capture system were used to determine tibial accelerations, vertical ground reaction forces and footstrike patterns in each condition, respectively. Comfort perception was indicated on a 150 mm Visual Analogue Scale. A 2 (speed) × 3 (footwear) repeated measures ANOVA was used to examine the main effects of shoe cushioning and running speeds. Results Greater tibial shock (P < 0.001; η2 = 0.80) and impact loading (P < 0.001; η2 = 0.73–0.87) were experienced at faster running speeds. Interestingly, shoes with regular-cushioning or best-cushioning resulted in greater tibial shock (P = 0.03; η2 = 0.39) and impact loading (P = 0.03; η2 = 0.38–0.68) than shoes with better-cushioning. Basketball players continued using a rearfoot strike during running, regardless of running speed and footwear cushioning conditions (P > 0.14; η2 = 0.13). Discussion There may be an optimal band of shoe cushioning for better protection against TSF. These findings may provide insights to formulate rehabilitation protocols for basketball players who are recovering from TSF.

Tibial Acceleration and Spatiotemporal Mechanics in Distance Runners During Reduced-Body-Weight Conditions

Context:Treadmills that unload runners via a differential air-pressure (DAP) bladder (eg, AlterG Anti-Gravity Treadmill) are commonly used to reduce effective body weight (BW) in a clinical setting. However, the relationship between the level of unloading and tibial stress is currently unknown.Objective:To determine the relationship between tibial impact acceleration and level of BW unloading during running.Design:Cross-sectional.Setting:University motion-analysis laboratory.Participants:15 distance runners (9 male, 6 female; 20.4 ± 2.4 y, 60.1 ± 12.6 kg).Main Outcome Measures:Peak tibial acceleration and peak-to-peak tibial acceleration were measured via a uniaxial accelerometer attached to the tibia during a 37-min continuous treadmill run that simulated reduced-BW conditions via a DAP bladder. The trial began with a 10-min run at 100% BW followed by nine 3-min stages where BW was systematically reduced from 95% to 60% in 5% increments.Results:There was no significant relationship between level of BW and either peak tibial acceleration or peak-to-peak tibial acceleration (P > .05). Both heart rate and step rate were significantly reduced with each 5% reduction in BW level (P < .01).Conclusions:Although ground-reaction forces are reduced when running in reduced-BW conditions on a DAP treadmill, tibial shock magnitudes are unchanged as an alteration in spatiotemporal running mechanics (eg, reduced step rate) and may nullify the unloading effect.