2.3.2. Training Load and Energy Expenditure during Training
The Firstbeat Sport Sensor and Bodyguard 2 (Firstbeat Technologies Oy, Jyväskylä, Finland) were employed to monitor training load and energy expenditure during training. Training impulse (TRIMP) is an indicator generated by the FirstBeat algorithm, used to quantify the training load accumulated during a session; this was calculated based on the athlete’s heart rate reserve and the exercise duration of the session. TRIMP takes into account the intensity of exercise as calculated using the heart rate (HR) reserve method and the duration of exercise.