Abstract: The present disclosure describes selector pin for a weight stack of a weight exercise machine, and a bolt element for such a selector pin. The bolt element has two first contact points (22.1) positioned along the length of the bolt element (22) on a first side of the bolt element (22), and a second contact point (22.2) between the first contact points on a second side opposite to the first side. The first contact points (22.1) being configured to engage with the weight plate during an exercise, and the second contact point (22.2) being configured to engage with the centre selector shaft. The bolt element may further have a stress sensor configured to determine mechanical stress of the bolt element caused by forces generated by the weight plate and the selector shaft acting on the first and second contact points (22.1; 22.2) of the bolt element (22).

Abstract: An apparatus for energy expenditure estimation includes a heart rate sensor for producing a heart rate value indicative of a heart rate of an individual, a heat-flux sensor for producing a heat-flux value indicative of a heat-flux flowing through a measurement area on the skin of the individual, and a processing system communicatively connected to the heart rate sensor and the heat-flux sensor. The processing system is configured to produce an estimate of the energy expenditure based on the heart rate value and the heat-flux value. The use of the heat-flux value improves the accuracy of the estimation especially during low-intensity exercise and rest, when both heart rate and acceleration values often fail to provide information meaningful enough for energy expenditure estimation.

Abstract: A data processor maintains an electronic exercise program, which defines exercise sessions defining exercise sets for a subject on one or more exercise apparatuses. The data processor makes a selection (306) between an exercise set (320) and a performance test (308). If a set is selected, instructions relating to the set are given. Each repetition is detected, a risk of injury is assessed, and if a threshold is exceeded, instructions for reducing likelihood for injury are given. Repetitions are counted until detection of a last repetition in the set (410). Feedback is given after the last repetition. If a performance test (308) is selected, instructions relating to the test are given. Subject's performance is monitored until termination of the test. After the test, the exercise program (310) is adapted based on the monitored performance data.