The XPO Trainer used in this inquiry is a novel device which provides low rolling resistance at low speeds with an immediate and automatic proportional gain in resistance with increased speed. Resistance exercise (RE) has been shown to induce many positive benefits to the body and mind, including hypertrophy of muscles, increased muscle performance, cardiovascular benefits, decrease risk of mortality, and decrease the risk of functional limitations.PURPOSEExamine the impact of pushing a constant resistance on gait and neuromuscular activation at low and high speeds in young, seemingly healthy adults.METHODSThe study consisted of 21 healthy adult males and females (age: 25.07±3.46 years, weight: 148.2±25.96 lbs, height: 66.57±4.14 inches). Each participant wore surface electromyography electrodes on their dominant leg for their quadriceps (QUAD), hamstring (HAM), anterior tibialis (TA), and gastrocnemius (GA). First, the maximal voluntary isometric contractions were gathered for each muscle. Then, participants performed 3 trials of 4 conditions: walking, walking and pushing, running, and running and pushing. After the data was normalized as a percentage (0–100%) for the gait tasks and the muscle activation amplitude, a repeated measures ANOVA was performed with the SPSS 24 system.RESULTSThe QUAD muscle exhibited a significantly higher muscle activation (P≤0.05) between walk (45.39±24.43) and walk push (74.40±56.73) tasks. Additionally, there is a significantly higher muscle activation (p≤0.05) between GA (81.85±37.84) and QUAD (46.06±23.93) during the walking task. A significant difference (p≤.05) was found between GA (0.33±0.17) and HAM (0.47±0.17) muscle activation timing during walking activity. During the walking activity, maximal muscle activation occurred in the GA muscle earlier than the HAM muscle. Additionally, there was a significant difference (p≤.05) in timing of the TA (0.43±0.17) vs QUAD (0.55±0.18), as well as the GA (0.41±0.10) vs the QUAD(0.55±0.18). TA and GA activation occurred significantly earlier than the QUAD activation during the walk and push task.CONCLUSIONWith the constant resistance sled being a novel device, it is important to understand how it affects the activation and response of muscles during different activities. Based on the results, patients can benefit from utilizing the sled in combination of walking and running to either promote a higher or lower muscle activation. With patients with weak QUADs or in need of QUAD strength training, a walking task is advocated. Additionally, if the goal of the intervention is to focus on endurance of the TA and GA, two of the main muscles used in postural balance, walking with the sled is recommended. Knowing all of these effects on muscle activation utilizing a constant resistance sled trainer will allow for more effective exercise training.