Table 1.

Experimental protocol of competitive swimmers to evaluate the role of the underwater swimming on biomechanical and physiological parameters.

Free underwater condition	Set 1	2 × 75 dive on 2′30	200 m pace (swimmers asked to count the underwater kicks per lap)
Constrained underwater conditions	Set 2	2 × 75 dive on 2′30	200 m pace with two additional underwater kicks in each underwater section after start and turns
	Set 3	2 × 75 dive on 2′30	200 m pace with the maximum distance covered in each underwater section after start and turns