Table 6 Summary of study kinetic data

Hochstein et al. [44]

1 national swimmer (F)

20 m max UUS trial from a standing start in the prone body position and 2D Particle Image Velocimetry (PIV)

Drag coefficient was compared between computational fluid dynamics (CFD) and experimental conditions, and the analysis was divided into glide and undulatory phases

CFD

Exp

0.3

0.25–0.29

2.98

NA

Jensen and McIlain [45]

2 international swimmers (1 M, 1F)

No information was provided on the number of trials, distance of each trial, trial goals, e.g. max speed or percentage of normal kick frequency performed. Anthropometric measurements were taken of the lower extremity of the swimmers and used to formulate a geometric representation of the segments’ inertial properties. Drag forces, joint forces and moments of force were then calculated using the segment inertial properties and kinematic data of the UUS

− 45.5

92.35

Lyttle and Blanksby [42]

Study 1: 40 national swimmers (M)

Study 2: 16 national swimmers (M)

Study 1: Towed in a prone position 25 m at a depth of 0.6 m underwater. At this depth, swimmers were towed at 1.6; 1.9; 2.2; 2.5 and 3.1 m s⁻¹. Drag force was recorded using a unidirectional load cell

Study 2: Towed in a prone position 25 m at a depth of 0.5 m underwater at velocities 1.6; 1.9; 2.2; 2.5 and 3.1 m s⁻¹. Net force was recorded using a unidirectional load cell

1.6

21.3 ± 12.6

58.1 ± 9.3

1.9

− 48.3 ± 14.8

80.4 ± 10.0

2.2

− 87.0 ± 18.3

109.4 ± 11.1

2.5

− 122.1 ± 20.0

140.5 ± 14.4

3.1

− 192.7 ± 22.0

204.1 ± 19.2

Lyttle et al. [43]

16 national swimmers

Towed in a prone position 25 m underwater at velocities 1.6, 1.9, 2.2, 2.5 and 3.1 m s⁻¹ performing prone undulatory kicking. During each trial, net force was recorded using a unidirectional load cell

1.6

− 21.3 ± 12.6

1.9

− 48.3 ± 14.8

2.2

− 87.0 ± 18.3

2.5

− 122 ± 20.0

3.1

− 193 ± 22.0