Characterization of Leg Push Forces and Their Relationship to Velocity in On-Water Sprint Kayaking

Abstract

The purpose of this work was to describe the leg-muscle-generated push force characteristics in sprint kayak paddlers for females and males on water. Additionally, the relationship between leg pushing force characteristics and velocity was investigated. Twenty-eight paddlers participated in the study. The participants had five minutes of self-chosen warm-up and were asked to paddle at three different velocities, including maximal effort. Left- and right-side leg extension force were collected together with velocity. Linear regression analyses were performed with leg extension force characteristics as independent variables and velocity as the dependent variable. A second linear regression analysis investigated the effect of paddling velocity on different leg extension force characteristics with an explanatory model. The results showed that the leg pushing force elicits a sinus-like pattern, increasing and decreasing throughout the stroke cycle. Impulse over 10 s showed the highest correlation to maximum velocity (r = 0.827, p < 0.01), while a strong co-correlation was observed between the impulse per stroke cycle and mean force (r = 0.910, p < 0.01). The explanatory model results revealed that an increase in paddling velocity is, among other factors, driven by increased leg force. Maximal velocity could predict 68% of the paddlers’ velocity within 1 km/h with peak leg force, impulse over 10 s, and stroke rate (p-value < 0.001, adjusted R-squared = 0.8). Sprint kayak paddlers elicit a strong positive relationship between leg pushing forces and velocity. The results confirm that sprint kayakers’ cyclic leg movement is a key part of the kayaking technique.

Magnitude and Shape of the Forces Applied on the Foot Rest and Paddle by Elite Kayakers

“…If a longer compression force duration would be associated with a greater range of motion of the knee, results are in line with a previous study [3], that suggested that greater knee amplitude are associated with elite kayakers' performance. Nilsson and colleagues [1] observed that kayak speed decreased by 16% with the restriction of movement of the lower limbs and also reported a high correlation between pushing forces and kayak velocity, which suggests that the force applied by the lower limbs considerably influences the kayaking performance [6]. Previously, Begon and colleagues [5], based on computer modeling to access the lower limb contribution to kayak performance, suggested that the legs produce 6% of the total propulsion on a sliding kayak ergometer.…”

“…These results were confirmed in an on-water kayaking study, also comparing restricted and unrestricted, and concluded that the restriction of lower limbs leads to a significant reduction of the kayak velocity (−16%) and a decrease of the bilateral mean stroke force (−21%), however, in terms of the time pattern of the occurrence of the peak force on the foot rest and foot strap, there were no significant changes [1]. Futhermore, the impulse of the push forces on the foot rest over 10 s showed the highest correlation to maximum kayak velocity [6].…”

“…A few studies [1,6,9] have been dedicated to the analyses of the forces applied on the foot rest and foot strap, and none have analyzed the magnitude and shape of the force-time curves of compression (push foot rest forces), tension (pull foot strap forces), and paddle, as well as the synchronization between these forces in elite kayakers. Therefore, the goals of the present study were to describe the magnitude and shape of the force-time curves of compression and tension applied on the foot rest and foot strap, respectively, by studying elite kayakers and their performance on a kayak ergometer, and simultaneously, to analyze the synchronization and timing of these forces with the paddle force-time curves.…”

Quantifying paddling kinematic through muscle activation and whole body coordination during maximal sprint of different duration on a kayak ergometer: a pilot study

“…However, one should be cautious not to interpret these findings as increasing stroke length through a delayed exit of the blade from the water that would impair boat speed and consequently increase drag force (Gomes et al 2015). Instead, international elite athletes of better performance level distinguishes from national level athletes by a greater range of motion in knee extension, increasing pelvis and trunk rotation which ultimately increased stroke length through a well forward catching phase (Limonta et al 2010; Klitgaard et al 2021). However, they maintain the exit phase once the blade reaches the vertical position to quickly initiate the contralateral catching phase while reducing ineffective portion of the stroke (Gomes et al 2015).…”

“…Leg contribution in flatwater kayaking should also not be discarded. Providing the feet are strapped on the footrest, the kayakers performed push and pull actions with their legs to enhance pelvis and trunk rotation (Nilsson et Rosdahl 2016; Limonta et al 2010; Klitgaard et al 2021) (Nilsson et Rosdahl 2016) estimated to 0.2 seconds the duration of the synchronized period between leg extension and paddle thrust. Although of short duration, synchronization between leg extension, pelvis, and trunk rotation, as well as paddle thrust, needs to be finely refined to provide gain in boat velocity quantified from 6% (Begon, Colloud, et Sardain 2010, 201) to 16% (Nilsson et Rosdahl 2016).…”