The purpose of this study was to analyse the effects of an exhaustive exercise on arm coordination and intracyclic velocity variations (IVV) to better understand the ways in which they are modified under fatigue conditions. Seventeen competitive swimmers performed a 200-m all-out test and a set of two 25-m (before and after the 200-m) at maximal intensity to measure stroking parameters, IVV, and the relative duration of the different parts of the stroke cycle and identify the model of arm coordination by using the index of coordination (IdC). Results showed an increase in the relative duration of the propulsive time, which induced a change in arm coordination as fatigue developed in relation to a decrease in stroke length (SL) and stroke rate (SR) (p<0.05). The evolution of IdC corresponds to a reduction of the non-propulsive lag time between the two arms' propulsive actions. Despite these modifications, IVV were not significantly modified (p<0.05). The present results highlighted that IdC and relative durations of each part of the cycle (particularly the pull phase) could be assessed to complete the "SL x SR" model and to partly understand the technique modifications under fatigue condition.

A variety of testing procedures are used to assess the effects of particular treatments on the training status of athletes. The present study aims to investigate the reproducibility of selected tests in swimming. Sixteen trained swimmers performed three kinds of test: 1) Constant Distance Test (CDT), 2) Constant Time Test (CTT), and 3) Constant Velocity Test (CVT). The analysis of the reproducibility was based on a test-retest procedure. The test-retest performances were highly correlated for the three kinds of test (r = 0.98, 0.98, and 0.93 for CDT, CTT and CVT, respectively). The mean Coefficient of Variation (CV) was computed between test-retest for each subject and each procedure. A repeated measures one-way ANOVA showed that CVT was significantly less reliable (CV = 6.46 +/- 6.24 %) than CDT and CTT (CV = 0.56 +/- 0.6 0 % and 0.63 +/- 0.54 % respectively) (p < 0.001). Psychological factors and a lack of familiarity with CVT (not extensively used during training session) could explain its greater variability. Thus, CDT and CTT seem to be the most reliable tests to detect the smallest meaningful change in the training status of swimmers. Post-hoc power calculations of the experimental design showed the sample size would have to increase to 80, 113, and 228 subjects for CWT, CDT and CPT respectively, to reach a power of 80 %. The minimal detectable differences have to be calculated to ensure a real effect of a particular treatment on a group of swimmers, according to the kind of test used.

The aim of this study was to analyse the variations of stroking parameters (speed, stroke length, stroke rate, and stroke index) associated with the 200 m front crawl competitive performance improvement. Two races completed by 17 top swimmers were analysed in the 200 m freestyle final of French or European championships, each final being separated by two years. All the swimmers' performances were bettered in the second race (mean +/- SD: 113.44 +/- 2.50 vs 111.78 +/- 2.71 s; p < 0.01) and were associated with a significant increase of stroke rate without variation of average stroke length and stroke index values (p > 0.05). Swimmers emphasized the first part of the race, with higher speed in the first three lengths, higher stroke rate in the first two lengths and lower stroke length in the first one. Stroke length and stroke rate variations were highly correlated (r = 0.98; p < 0.05). In 11 of the 17 swimmers, the improvement was concomitant with a decrease in stroke length and an increase in stroke rate. Only one swimmer's improvement was associated with a substantial increase in stroke length. These results highlighted that stroke length and stroke index cannot be considered as the only parameters linked to improvement in a 200 m crawl in adult swimmers competing at high standard. Moreover, an increase in stroke rate associated with a slight decrease in stroke length should not be considered as ineffective, especially at top standard.