The aim of this study was to compare the intra-cyclic velocity graphs of breaststroke swimmers at two skill levels in relation to their movement phases. Two groups of nine male swimmers were videotaped underwater at three swimming race paces corresponding to their actual competitive times for the 200-m, 100-m and 50-m breaststroke. Their forward intra-cyclic hip velocity was recorded with a velocity-meter. The breaststroke cycle was divided into four phases: leg propulsion, leg-arm lag phase, arm propulsion, and arm and leg recovery. From the velocity-time data, the following parameters were computed: an index of velocity fluctuations (IVF), the distance covered during each stroke phase, and an acceleration-deceleration time ratio (ADTR). The main results showed that in both groups of swimmers, when the race pace increased, the distance covered during the leg-arm lag phase decreased, while the other swimming phases remained stable. When expressed in relative values, the percentage of distance covered during the leg-arm lag phase decreased. In nonelite swimmers, the percentage of distance covered in the other stroke phases increased significantly, while only a tendency was noted in the elite group. Elite swimmers demonstrated a higher ADTR at the 50-m pace than at their 100-m and 200-m paces. An inter-group comparison showed that elite swimmers had higher values for the IVF and ADTR, which indicated their capacity to accelerate to boost the swim and highlighted the relevancy of these factors to discriminate skill level.

Objective: To establish the relation between handball playing, passive hip range of motion (ROM), and the development of radiological hip osteoarthritis (OA) in former elite handball players. Two related issues are addressed: (a) the relation between long term elite handball playing and the incidence of hip OA; (b) the relations between hip ROM, OA, and pain. Methods: Data on 20 former elite handball players and 39 control subjects were collected. A questionnaire yielded personal details, loading patterns during physical activity, and previous lower limb joint injury. Bilateral radiographs were analysed to diagnose and classify hip OA. Passive hip ROM was measured bilaterally with a goniometer. Results: A close relation was found between long term elite handball practice and the incidence of hip OA: 60% of the handball players were diagnosed with OA in at least one of the hip joints compared with 13% of the control subjects. Passive ROM measured in the handball players was significantly lower for hip flexion and medial rotation and higher for abduction, extension, and lateral rotation than the control values. The handball players with OA reported less pain in the hip joints during daily activities than the control subjects with OA. Conclusion: The risk of developing premature hip OA seems high for retired handball players and significantly greater than for the general population. Pain and discomfort represent two difficult diagnostic challenges to the sports physician, as the repetitive nature of movements that are specific to handball can lead to alterations that are rarely seen in the general population.

An imbalance in the agonist/antagonist ratio has been identified as a pathologic factor. Using an isokinetic dynamometer, several studies have investigated the loss of quadriceps strength due to fatigue, but few have explored this phenomenon in the hamstrings. This study assessed the decline in strength of the hamstring and quadriceps muscles with fatigue. The goal was to determine whether a divergence in the decline in strength occurs that would affect the hamstring to quadriceps ratio of endurance. Twenty-seven professional soccer players were selected for endurance testing to evaluate fatigue on an isokinetic dynamometer. The decline in hamstring strength was significantly greater than that of the quadriceps after 15 repetitions for the dominant leg and after 40 repetitions for the nondominant leg. This study also revealed a decline in the endurance ratio compared with the maximal strength ratio in the dominant leg after 30 repetitions. In fatigue states, the decline in hamstring strength diverges from that of the quadriceps in both legs. This difference in resistance to fatigue provokes an imbalance that may affect the stabilizing function of the thigh muscles. These results can be considered as indicators of an increased risk of injury during exhausting effort.

Maximal or peak oxygen uptake (V˙O2 max and V˙O2 peak , respectively) are commonly measured during graded exercise tests (GXTs) to assess cardiorespiratory fitness (CRF), to prescribe exercise intensity and/or to evaluate the effects of training. However, direct measurement of CRF requires a GXT to volitional exhaustion, which may not always be well accepted by athletes or which should be avoided in some clinical populations. Consequently, numerous studies have proposed various sub-maximal exercise tests to predict V˙O2 max or V˙O2 peak . Because of the strong link between ratings of perceived exertion (RPE) and oxygen uptake (V˙O2), it has been proposed that the individual relationship between RPE and V˙O2 (RPE:V˙O2) can be used to predict V˙O2 max (or V˙O2 peak) from data measured during submaximal exercise tests. To predict V˙O2 max or V˙O2 peak from these linear regressions, two procedures may be identified: an estimation procedure or a production procedure. The estimation procedure is a passive process in which the individual is typically asked to rate how hard an exercise bout feels according to the RPE scale during each stage of a submaximal GXT. The production procedure is an active process in which the individual is asked to self-regulate and maintain an exercise intensity corresponding to a prescribed RPE. This procedure is referred to as a perceptually regulated exercise test (PRET). Recently, prediction of V˙O2max or V˙O2 peak from RPE:V˙O2 measured during both GXT and PRET has received growing interest. A number of studies have tested the validity, reliability and sensitivity of predicted V˙O2 max or V˙O2 peak from RPE:V˙O2 extrapolated to the theoretical V˙O2 max at RPE20 (or RPE19). This review summarizes studies that have used this predictive method during submaximal estimation or production procedures in various populations (i.e., sedentary individuals, athletes and pathological populations). The accuracy of the methods is discussed according to the RPE:V˙O2 range used to plot the linear regression (e.g., RPE9–13 versus RPE9–15 versus RPE9–17 during PRET), as well as the perceptual endpoint used for the extrapolation (i.e., RPE19 and RPE20). The V˙O2 max or V˙O2 peak predictions from RPE:V˙O2 are also compared with heart rate-related predictive methods. This review suggests that V˙O2 max (or V˙O2 peak ) may be predicted from RPE:V˙O2 extrapolated to the theoretical V˙O2 max (or V˙O2 peak) at RPE20 (or RPE19). However, it is generally preferable to (1) extrapolate RPE:V ˙ O 2 to RPE19 (rather than RPE20); (2) use wider RPE ranges (e.g. RPE ≤ 17 or RPE9–17) in order to increase the accuracy of the predictions; and (3) use RPE ≤ 15 or RPE9–15 in order to reduce the risk of cardiovascular complications in clinical populations.

PurposeInvestigate the physiological responses and rating of perceived exertion (RPE) in elite karate athletes and examine the relationship between a subjective method (Session-RPE) and two objective heart-rate (HR)-based methods to quantify training-load (TL) during international karate competition.MethodsEleven karatekas took part in this study, but only data from seven athletes who completed three matches in an international tournament were used (four men and three women). The duration of combat was 3 min for men and 2 min for women, with 33.6±7.6 min for the first interval period (match 1–2) and 14.5±3.1 min for the second interval period (match 2–3). HR was continuously recorded during each combat. Blood lactate [La-] and (RPE) were measured just before the first match and immediately after each match.ResultsMeans total fights time, HR, %HRmax, [La-], and session-RPE were 4.7±1.6 min, 182±9 bpm, 91±3%, 9.02±2.12 mmol.L-1 and 4.2±1.2, respectively. No significant differences in %HRmax, [La-], and RPE were noticed across combats. Significant correlations were observed between RPE and both resting HR (r=0.60; P=0.004) and mean HR (r=0.64; P=0.02), session-RPE and Banister training-impulse (TRIMP) (r=0.84; P<0.001) and Edwards TL (r=0.77; P<0.01).ConclusionInternational karate competition elicited near-maximal cardiovascular responses and high [La-]. Training should therefore include exercise bouts that sufficiently stimulate the zone between 90 and 100% HRmax. Karate coaches could use the RPE-method to follow competitor's competition loads and consider it in their technical and tactical training.