Why not attach the position transducer to the athlete’s waist for barbell jump squats instead of attaching to barbell?

Many labs and teams do attach the transducer to the belt rather than bar. There are no strict methodologies at this time and it depends on movement, setting, athlete experience, personal preference. I would test each and see which provides more representative data. Caution re attaching to waist belt – that belt position must be secure so it can’t slip. Belt slippage causes inaccuracy data recorded re squat jumps Counter Movement Jumps etc.