Participants in the control group participate in balance and tone training, as described by Liu-Ambrose et al. [35]. This training combines stretching, mobility, stability, balance, and relaxation exercises, which are combined according to a standardized exercise catalogue. We chose this control method to minimize confounders (such as social interaction), which might infuence the results. The intervention period, training duration, and training frequency are the same as in the experimental group. Similar to the experimental group, the participants perform a warm-up and cool-down phase and are supervised by a sports scientist, furthermore, the training documentation is based on the measured heart rate, lactate concentration and perception of performance. However, instead of regulating the training intensity according to the preceding results of the lactate threshold test, the main objective was to perform the exercises as correctly as possible. If a participant can perform the exercises over the entire required period of time with only little efort, the training personnel can suggest options to increase the difculty of the exercises (e.g., crunching with arms folded behind the head instead of on the chest)