Biomechanical analysis and reproducibility of speed based on perception in overground and treadmill running

Details

Supervisors

Nguyen, Anh Phong

Faculty

Faculté des sciences de la motricité

Degree label

Master [120] en sciences de la motricité, orientation générale, à finalité spécialisée: kinésithérapie musculo-squelettique

Abstract

Background : The popularity of running has risen in popularity globally due to its accessibility and health benefits. However, the high incidence of running-related injuries (RRIs) is worrying. Key factors influencing RRIs include training volume, previous injury history, and gender. Treatment often involves consultation with physiotherapists, emphasizing their crucial role in recovery. Recent studies explore the biomechanical differences between running on motorized treadmills (MT) and on land, bringing light on potential differences in running biomechanics and perceived exertion. This research aims to analyse data from Runscribe pods to identify biomechanical differences between MT and athletic track running, building upon previous findings with an additional sample. Objectives : 1. Is the RPE scale reliable and reproducible for controlling exercise intensity in the same condition? 2. Are runners capable of reproducing the same speed at the same intensity in 2 different conditions: on overground and on motorized treadmill? 3. Is running on a motorized treadmill biomechanically comparable to overground running? Study design : An observational cross sectional study Methods : 55 healthy people were recruited. They were asked to run 6 times 1 km, 4 times at an intensity of 3/10 (2 times on treadmill and track) and 2 times at an intensity of 8/10 (1 time on treadmill and track). During the experiment, biomechanical data (via Runscribe pods) and physiological data (HR with heart rate monitor) were taken. Participants were also asked how they felt on an RPE scale after running. Results : 1. ICC reported excellent reliability for 3/10 RPE running speed for both conditions with a high correlation of 0,97 (95% IC [0,945 ; 0,981]) on overground and 0,93 (95% IC [0,88 ; 0,959]) on treadmill. 2. Participants choose slower speed with lower heart rate and RPE on MT than on overground for the two levels of RPE. At 3 of RPE : There is a significant difference for speed of -2,18 km/h (p<0,001, 95% IC [-2,5 ; -1,8], Cohen d: 1,11), for the perceived effort of -0,25 (p<0,001, 95% IC [-0,38 ; -0,01], Cohen d: 5,52) and for the heart rate of -10,8 bpm (p<0,001, 95% IC [-13,1 ; -8,5], Cohen d: 0,62). At 8 of RPE : There is a significant difference for speed of -1,58 km/h (p<0,001, 95% IC [-2,08 ; -1,08], Cohen d: 0,61), for the perceived effort of -0,51 (p<0,001, 95% IC [-0,76 ; -0,25], Cohen d: 0,80) and for the heart rate of -5,47 bpm (p<0,001, 95% IC [-8,01 ; -2,93], Cohen d: 0,53). Runners feel less tired on MT but run slower than on overground. 3. For the first level of RPE (3/10), there are many biomechanical differences between MT and overground. There is a strong significant mean difference for the contact ratio with 79,32% for overground and 87,38% for MT (p<0,0001, Cohen d: 0,81). There are significant mean differences for horizontal GRF of -1,43N (p<0,0001, Cohen d: 0,93), for vertical GRF of -3,64N (p<0,0001, Cohen d: 0,85), for step rate of -4 steps/min (p=0,0003, Cohen d: 0,50), for step length of -0,22m (p<0,0001, Cohen d: 0,89), for total steps of 224 steps/km (p<0,0001, Cohen d: 0,84) and for ground shocks of -2,76 Gs (p<0,0001, Cohen d: 1,09). Runners make more steps that are shorter and less stressful on a MT at low RPE. Conclusion : RPE scales appear to be reliable tools for prescribing and controlling exercise intensity. The effort effectively perceived by runners is lower on MT than on overground for the two levels of RPE and MT running is characterized by a higher duty factor and a lower step length (At 3 of RPE) which decrease the risk of injury.