Energetics and mechanics of kicking with lifeguarding fins

Open-water lifeguarding is a physically demanding profession, especially at crowded beaches and in dynamic ocean environments. Lifeguards often use fins when performing rescues as they can improve performance and decrease fatigue. The purpose of this study is to compare the energetics and mechanics of kicking with three different pairs of lifeguarding fins (DaFiN Pro Classic, Viper V7, Duck Feet) to a pair of swim fins (Arena Powerfin Pro). Thirty-one lifeguards (22 men, 9 women; 24 ± 6 years old) completed a maximal graded kicking test in a swim flume wearing the Arena Powerfin Pro, followed by four randomized 5-min submaximal trials at ∼80% of their peak kicking speed (0.93 ± 0.17 m/s). Cost of kicking was significantly lower in DaFiN Pro Classic (684 ± 156 J/m) and Duck Feet (663 ± 156 J/m) compared to the swim fins (780 ± 145 J/m), but not with the Viper V7 fins (733 ± 152 J/m). Kicking intensity was reduced with all three lifeguarding fins relative to the swim fins and the Duck Feet fins had a reduced kicking intensity relative to the Viper V7 fins. All lifeguard fins elicited a lower kick cadence than the swim fins and there were no differences in cadence among the lifeguarding fins. These findings suggest that lifeguard-specific fins have metabolic and biomechanical advantages relative to swim fins. Lifeguard agencies should consider kicking mechanics and energetics, alongside subjective measures, when selecting fins for their lifeguards.