Exercise phase
0/25/50/75/100% of the trajectory (agreed variant 'a')
Short definition
A key point of the isometric exercise cycle: 0% start, 25/50/75% intermediate, 100% finish.
Full definition
A phase sets joint angles (joint_angles_json) and grip height: height_fraction is grip height as a fraction of user stature, from which chain length L_chain = H_phase − 30 − 98 mm and link count are derived. The MIDA catalog assigns muscle contributions per phase. Stored in ExercisePhase (unique exercise+phase pair); in frequency analysis the phase also sets the BioSim pose (elbow angle).
Examples
Phase 50% of biceps curl: elbow angle ≈ 37.5°.