Swimming coaches know that a swimmer’s assessment must be specific and ecological. Thus, it is critical to select and employ adequate methodologies. The tethered swimming method can be useful and valid, in addition to being simple to apply. Regular use of this methodology can give coaches tools to intervene with their swimmers and increase performance. The main objective of this manuscript was to analyze the potential for measuring the propulsive forces exerted in water as a biomechanical tool for evaluating and training competitive swimmers. The key results demonstrated that this methodology allows (i) the assessment of upper limb bilateral kinetic asymmetries; (ii) the evaluation of the contribution of the upper and lower limb actions, inferring about the (un)balance between strength and coordination; (iii) the examination of the relationship between the intracyclic variations in speed and force; (iv) the evaluation of the effective application of force to the speed of high-level swimmers. Furthermore, this manuscript suggests advances using mathematical modeling and artificial intelligence (AI) that will provide significant insights into swimming performances. AI developments will promote its integration into sports optimization, and swimming will be no exception.
The term “tethered swimming” (TS) emerged in the 1970s by Magel [
1]. Although he was the first to refer to this methodology, his work was based on ideas previously developed by Karpovich [
2] and Mosterd [
3]. In the 1930s, Karpovich moved forward with the first studies that aimed to analyze the relationship between force and resistance. In 1939, he presented an apparatus that consisted of using a kymograph to graphically represent the propulsive forces performed [
4]. Although the intention was to better understand the magnitude of the applied force, the instrumentation used only allowed the estimation of the average forces exerted by a swimmer by inverse dynamics. Twenty years later, Mosterd [
3] conducted his doctoral work at the University of Utrecht, arguing that
“This research was carried out with the intention of contributing to the direct measurement of performance for a more scientific basis of swimming training in general and of the best swimmers in particular. By applying muscle training and interval training, the ability to apply force in swimming can increase considerably (…). It is necessary to first develop a good method for measuring propulsive forces and then determine from the research itself what influences your swimming training.”
The used apparatus (a dynamometer) allowed for the recording of the forces exerted, the breathing events, and the beginning of the cycles of action of the upper and lower limbs. This idea served as the basis for Magel [
1] to use a planimeter to estimate the propulsive forces in swimming, having used a three-minute test to characterize the production of force in the four swimming techniques. At that time, the curve average height (in millimeters) for each stroke was measured and then converted to average force values.
Knowing the relevance and validity of measurements performed in water, several studies have followed Magel by inferring the link between this test and swimming performances [
5,
6]. Yet, the technological limitations have inhibited the rapid achievement of results, blocking the determination of other variables and influences in swimming performances, as explained in previous literature reviews [
7]. Therefore, the tethered swim was a methodology that was adopted poorly in its first years.
Another methodological issue was the duration of the test. This perception forced researchers to reduce the test time from 3 min to durations closer to those used in competition (e.g., 5, 10, 20, 30, 45, and 60 s). This reduction stimulated several perspectives on the duration of use in the tethered swim. Cortesi et al. [
8] analyzed the relationship between performance in events of 50, 100, and 200 m with TS tests of 15, 30, 45, and 60 s, observing a greater relationship between the shorter distances (50 and 100 m) and the 30 s duration. Moreover, 30 s at maximum intensity is like the Wingate test protocol, allowing the acquisition of relevant physiological data for the swimmer’s evaluation, namely, the anaerobic mechanisms of energy production [
9]. Therefore, to bridge the gap between biomechanical and bioenergetic domains, physiological ecology must be ensured to guarantee results that provide an adequate interpretation.
This entry is adapted from the peer-reviewed paper 10.3390/encyclopedia4030067
