Effect of incline on lower extremity muscle activity during sprinting

Abstract

This study aimed to investigate the effect of incline on neuromuscular mechanisms in uphill sprint running. Nine male college sprinters performed 5-sec constant speed running trials on a motorized treadmill at 7.5 m/s. Each trial was conducted under different inclined conditions (level and 5.0% grade). Surface electromyography (EMG) was recorded from 6 muscles of the lower limbs, including gluteus maximus, gluteus medius, rectus femoris, vastus lateralis, biceps femoris, and lateral gastrocnemius lateralis. We found higher muscle activity in all muscles during the stance phase in uphill sprinting except for rectus femoris and vastus lateralis. Higher muscle activation during the recovery phase was found in the rectus femoris muscle in uphill sprinting. These muscle activity adaptations in uphill sprinting were paralleled by higher step frequency and shorter step length. Our results suggest that lower limb muscle activity can meaningfully adapt to sprint-specific demand in uphill running.

Training to Improve Pro-Agility Performance: A Systematic Review

“…Interestingly, the largest per session training effects were noted in studies that included incline sprinting (Ferley et al, 2020;Kavaliauskas et al, 2017), while level ground sprints were completed in all other sprint training interventions (Chan et al, 2018;Ferley et al, 2020;Markovic et al, 2007;Moran et al, 2018;Toyomura et al, 2018). The reason for the larger effects may be attributed to: 1) the effect of greater hip flexion involved with incline sprinting, as well as a greater force demands, similar to that of resisted sprinting (Okudaira et al, 2021); 2) the younger age of athletes, where sprint training may be more effective in those pre-PHV (Bourgeois et al, 2017); and, 3) the sprint duration Journal of Human Kinetics -volume 85/2022 http://www.johk.pl (i.e., 6-10 s) and/or distance (i.e., 20 m), may allow for higher intensity performance, utilization of stopping characteristics and greater relevance to that performed in the pro-agility. Overall, the improvements were significant when performing incline sprinting at a 5%-30% gradients with 6-30 s duration (Ferley et al, 2020;Kavaliauskas et al, 2017).…”

“…Sprint training, specifically inclined sprint training, was found to have the largest per session training effect. This could be attributed to the fact that inclined or resisted sprint training methods have been found to be particularly effective for enhancing accelerative capability ( Cahill et al, 2019 ; Okudaira et al, 2021 ). Given the large linear sprinting component and the limited number of changes of direction associated with the pro-agility shuttle, this makes sense since athletes are required to accelerate between each COD ( Brughelli et al, 2008 ).…”