Figure 3. Total energy expenditure (black dot, in kJ), Stroke Index (black square, in m2·-1) and Jerk Cost (black triangle, x103 m2·-5) in the 6 stroke rate conditions: spontaneous SR without any instruction (SRs) and imposed spontaneous SR (SRi), spontaneous SR-6 cycles (SRs-6), -3 cycles (SRs-3), +3 cycles (SRs+3), +6 cycles (SRs+6).