Muslce Oxygenation of the Quadricep Relative to Angle and Load

The purpose of the present study is to determine if the amount of oxygen in muscles during resistance exercise with different weights is related to changes in torque or knee joint angle. Participants will need to come to the lab three times over three weeks. On their first visit, we will test how strong their muscles are by testing the maximal weight that can be lifted in a single repetition of a knee extension referred to as a 1 repetition maximal (1RM) followed by exercise interventions during the second and third weeks. Each exercise session will have participants lift different amounts of weight. They will use two machines: the Biodex dynamometer, that maintains constant force during a knee extension and a standard weighted knee extension machine which has variable force outputs. Participants will perform these exercises against three levels of weight, making six tests in total. Their first exercise session will take about 70 minutes and the following sessions around 55-60 minutes. They will be provided a 5-minute break between each set of lifts to ensure they are fully rested. In total, participants will be exercising for about 25-30 minutes each visit, with the rest of the time spent resting. The weights will be different percentages of the heaviest weight participants can lift.