Effect of bodyweight support and incline running on electromyographic activity of triceps surae

During rehabilitation, body weight support (BWS) system is often used. It can be useful for optimizing time to return to practice by unloading joints and muscles. The present study aimed to explore the effects of Body Weight Support (BWS) and Incline Running (IR) on electromyographic activity (EMG) of triceps surae. We hypothesized that running with a slope of 7% and 30% of BWS could result in EMG comparable to level running. Eighteen healthy individuals participated in four randomized experimental sessions of ten minutes run at 10 km/h: 1) level running and 0% of BWS (LR), 2) incline running at 7% and 0% of BWS, 3) incline running at 7% and 15% of BWS, 4) incline running at 7% and 30% of BWS. EMG activity of Vastus Lateralis (VL), Gastrocnemius Lateralis (GL), Gastrocnemius Medialis (GM), and Soleus (SOL) was recorded during each 10 minutes running conditions and before two times during 30 seconds level running to normalize EMG activity (baseline). In addition, gait spatiotemporal parameters were taken at 1’, 5’ and 9 minutes and Rating of Perceived Exertion RPE was asked at 5’, 7’, and 10 minutes. Tests were conducted before and two minutes after running conditions. They included Counter Movement Jump (CMJ), and quadriceps low-frequency fatigue test.The results of the present study revealed a significant decrease in electromyographic activity of SOL at IR at 30% of BWS condition compared to IR without BWS (P < 0.002). Moreover, a significant decrease in electromyographic activity was observed of VL at IR at 30% of BWS condition compared to level running and IR conditions without BWS (P < 0.002 and P < 0.001). No changes were found in jump test (P = 0.246) and gait spatiotemporal parameters (P > 0.05) except in flight time (decrease with IR, increase with BWS, P < 0.006). Rate of Perceived Exertion was decreased with 30% of BWS (P < 0.002) and was no different to level running (P = 0.079). 15% of BWS (vs. uphill without BWS) did not significantly decrease the difficulty perception (P = 0.570). Also, low-frequency fatigue of the quadriceps was induced without BWS (P = 0.011) but not with 15% and 30% BWS (P > 0.05)Our results show that EMG activity of the triceps surae can be similar between running on a flat surface and running on a slope and 30% BWS. Furthermore, muscle fatigue, perceived exertion rate and spatio-temporal running parameters were similar between running on a flat surface and 30% BWS at 7% IR. Therefore, it can be useful to optimize the return time to practice and it is recommending for monitoring loads in Achilles Tendon and triceps surae. This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.