The purpose of this study is to evaluate the acute local skeletal muscle inflammatory response to thigh muscle (quadriceps) eccentric muscle actions. Eccentric muscle actions occur when the muscle is lengthening as it contracts. This is a pilot project to assess the degree of inflammatory biomarkers, called myokines, that are released locally in skeletal muscle tissue after an acute bout of resistance-exercise using a resistance-exercise machine called an isokinetic dynamometer.

The intervention will involve one session of maximal eccentric exercise of the knee extensor muscles (quadriceps) of the right leg. During the 24-hour period preceding the intervention, participants will be asked to refrain from any for of moderate-vigorous physical activity or exercise. Participants will perform 30 sets of 10 repetitions of maximal isokinetic eccentric knee extensions at 60 degrees/second with 1-minute of rest between each set. Before completing the exercise bout, each participant will be asked to remain in a seated position (resting) for 30-minutes and then provide a skeletal muscle biopsy using the modified Bergstrom with suction muscle biopsy technique from the vastus lateralis on the right leg. This will be done for the baseline assessment of 5 myokines including apelin, fibroblast growth factor-21, irisin, interleukin-6, and interleukin-15. Then the participants will complete the exercise bout as described above. They will then rest quietly in the laboratory for 3-hours and wait for the second skeletal muscle biopsy to be taken following this 3-hour wait.

Inclusion Criteria:

• 18-35 years old
• healthy
• recreationally active (>/= 150 minutes of moderate to vigorous physical activity per week for at least the past three months)

Exclusion Criteria:

• "yes" answer to the Get Active Questionnaire which screens for health conditions that may affect exercise ability