Local and Systemic Oxygen Saturation During 'Death by Squats' Exercise

Subjects in this study will be measured while they are engaged in an exercise protocol until maximum exertion, each in groups of three persons. The overall duration of the study is planned from April 2023 (start of recruitment) until December 2024 (finalization of data acquisition and analysis).

Subjects are executing a CrossFit workout which is planned as follows: Every minute, participants have to perform a given number of Airsquats (bodyweight squat). The first minute starts off with 10 repetitions, the remaining time can be used as a break. In minute two, 12 repetitions have to be done, in minute three 14 repetition, and so on. The subjects stick to this protocol until maximum exertion, in other words, until they are no longer able to execute the given repetitions within the actual minute. During the workout, heart rate is tracked by a 'Polar' chest strap, and the oxygen saturation of the vastus medialis and the triceps are measured using the 'Moxy' muscle oxygen monitor. Further, at rest and at maximum exertion, a blood lactate sample is taken (EKF lactate scout). Subjects rate their perceived exertion on the borg scale after quitting and indicate their primary reason for stopping (local fatigue in legs, systemic fatigue, time constraints).

Inclusion criteria

• being moderately to severely physically active al least 2 hours/week (all types of sport are eligible)

Exclusion criteria

• akute infections, musculoskeletal injuries
• chronic cardiovascular or pulmonary diseases (in case of uncertainty, we recommend appraisal from medical personnel)