Circulating soluble intercellular adhesion molecule-1 (sICAM-1) after exercise-induced muscular damage: Does the use of whole-body cryostimulation influence its concentration in blood?

As soluble intercellular adhesion molecule-1 (sICAM-1) was recently hypothesized to be a key player in the mechanisms involved in exercise-induced muscular damage (EIMD), we investigated its circulating concentration changes in athletes before and after EIMD with and without the use of whole-body cryostimulation (WBC; 3 min at -110 °C) at the exercise end and repeated once a day during 4 days. We previously characterized plasma specimens from 11 endurance athletes who performed twice (randomized crossover design) strenuous running leading to EIMD, followed by passive recovery or WBC. Muscle soreness and inflammatory response were observed in both cases but the use of WBC induced a significant reduction in these responses (PlosOne 2011; 6:e22748). We now found that sICAM-1 concentration slightly increased in both circumstances and remained elevated for 24 h (p < 0.01). However, no significant WBC effect was observed concerning sICAM-1 changes indicating that this compound is not a major player both in EIMD and WBC physiological impacts.

Low-frequency electrical stimulation combined with a cooling vest improves recovery of elite kayakers following a simulated 1000-m race in a hot environment.

This study compared the effects of a low-frequency electrical stimulation (LFES; Veinoplus(®) Sport, Ad Rem Technology, Paris, France), a low-frequency electrical stimulation combined with a cooling vest (LFESCR ) and an active recovery combined with a cooling vest (ACTCR ) as recovery strategies on performance (racing time and pacing strategies), physiologic and perceptual responses between two sprint kayak simulated races, in a hot environment (∼32 wet-bulb-globe temperature). Eight elite male kayakers performed two successive 1000-m kayak time trials (TT1 and TT2), separated by a short-term recovery period, including a 30-min of the respective recovery intervention protocol, in a randomized crossover design. Racing time, power output, and stroke rate were recorded for each time trial. Blood lactate concentration, pH, core, skin and body temperatures were measured before and after both TT1 and TT2 and at mid- and post-recovery intervention. Perceptual ratings of thermal sensation were also collected. LFESCR was associated with a very likely effect in performance restoration compared with ACTCR (99/0/1%) and LFES conditions (98/0/2%). LFESCR induced a significant decrease in body temperature and thermal sensation at post-recovery intervention, which is not observed in ACTCR condition. In conclusion, the combination of LFES and wearing a cooling vest (LFESCR ) improves performance restoration between two 1000-m kayak time trials achieved by elite athletes, in the heat.

Endurance and strength training effects on physiological and muscular parameters during prolonged cycling.

PURPOSE: This study investigated the effects of a combined endurance and strength training on the physiological and neuromuscular parameters during a 2-h cycling test. METHODS: Fourteen triathletes were assigned to an endurance-strength training group and an endurance-only training group. They performed three experimental trials before and after training: an incremental cycling test to exhaustion, a maximal concentric lower-limbs strength measurement and a 2-h cycling exercise. Physiological parameters, free cycling chosen cadence and the EMG of Vastus Lateralis (VL) and Rectus Femoris (RF) were analysed during the 2-h cycling task before and after a strength training programme of 5 weeks (three times per week). RESULTS: The results showed that the maximum strength and the isometric maximal voluntary contraction (isoMVC) after training were significantly higher (P<0.01) and lower (P<0.01) than those before training, respectively, in endurance-strength training group and endurance-only group. The physiological variables measured during the cycling tests and the progressive increase (P<0.01) in EMGi(VL) and EMGi(RF) throughout the 2-h cycling test did not differ between the two groups before and after training, except for the variation of EMGi(VL) over the cycle time which was stabilized during the second hour of the 2-h cycling test due to training in endurance-strength training group. The decrease in free cycling chosen cadence observed in pre-training (P<0.01) was also replaced by a steady free cycling chosen cadence for the endurance-strength training group during the second hour of exercise. CONCLUSION: This study confirmed the decrease in the free cycling chosen cadence with exercise duration and demonstrated that a specific combined endurance and strength training can prevent this decrease during a 2-h constant cycling exercise.

Muscle strength and metabolism in master athletes.

Knee extensor muscle strength and metabolism were examined in endurance trained young versus master athletes (10 elderly: 62.5+/-4.1 yr and 10 young: 26.2+/-2.4 yr). Before and immediately after a resistance strength training (RST), subjects performed a maximal isometric voluntary contraction (MVC) and a 10-min cycling test at a same relative intensity. During MVC, evoked contractions of the knee extensors muscles were performed to assess neuromuscular properties. Metabolism was assessed using oxygen uptake kinetics model. Before the RST session master athletes showed lower knee extensors MVC values than young subjects (257 vs. 354 N p<0.05) without any difference in oxygen kinetics (respectively for elderly and young: oxygen slow component (VO2(sc)): 231 vs. 214 ml . min(-1) and time constant (tau1): 27.8 vs. 25.1 s, p>0.05). After the RST session, a similar effect of fatigue was observed on muscular properties and oxygen kinetics whatever the group (respectively for elderly and young: MVC: -13.4 vs. -15.9%; VO2(sc): +11.8 vs.+25.2% and tau1: -15.4 vs. -13.9%). Our results suggest that the ability of master athletes to perform exercise at a given intensity is maintained despite a significant loss in strength with ageing.

Prior muscular exercise affects cycling pattern.

The aim of this study was to investigate the effect of concentric or eccentric fatiguing exercise on cycling pattern. Eleven well trained cyclists completed three sessions of cycling (control cycling test [CTRL], cycling following concentric [CC] or eccentric [ECC] knee contractions) at a mean power of 276.8 +/- 26.6 Watts. Concentric and eccentric knee contractions were performed at a load corresponding to 80 % of one repetition maximum with both legs. Before and after CTRL, CC or ECC knee contractions and after cycling, a maximal voluntary contraction (MVC) test was performed. Cardiorespiratory, mechanical and electromyographic activity (EMG) of the rectus femoris, vastus lateralis and biceps femoris muscles were recorded during cycling. A significant decrease in MVC values was observed after CC and ECC exercises and after the cycling. ECC exercise induced a significant decrease in EMG root mean square during MVC and a decrease in pedal rate during cycling. EMG values of the three muscles were significantly higher during cycling exercise following CC exercise when compared to CTRL. The main finding of this study was that a prior ECC exercise induces a greater neuromuscular fatigue than a CC exercise, and changes in cycling pattern.

Relationship between strength level and pedal rate.

The purpose of this study was to examine the relationship between strength capacity and preferred and optimal cadence in well trained cyclists. Eighteen cyclists participated in this study. Each subject completed three sessions. The initial session was to evaluate the maximal isokinetic voluntary contraction level of lower limb. The second session was an incremental test to exhaustion. During the third session subjects performed a constant cycling exercise (20 min) conducted at five randomly cadences (50, 70, 90, 110 rpm) and at the preferred cadence (FCC) at the power reached at ventilatory threshold. Cardiorespiratory and EMG values were recorded. A metabolic optimum (EOC) was observed at 63.5 +/- 7.8 rpm different from preferred cadence (FCC, 90.6 +/- 9.1 rpm). No difference was found between FCC and the neuromuscular optimal cadence (NOC, 93.5 +/- 4). Significant relationships were found between EOC, NOC and strength capacities (r = - 0.75 and - 0. 63), whereas FCC was only related with VO2max (r = 0.59). The main finding of this study was that during submaximal cycling energetically optimal cadence or neuromuscular optimum in trained cyclists was significantly related with strength capacity and whereas preferred cadence seems to be related with endurance training status of cyclists.

Relation between preferred and optimal cadences during two hours of cycling in triathletes.

OBJECTIVES: To determine whether the integrated electromyographic signal of two lower limb muscles indicates preferred cadence during a two hour cycling task. METHODS: Eight male triathletes performed right isometric maximum voluntary contraction (MVC) knee extension and plantar flexion before (P1) and after (P2) a two hour laboratory cycle at 65% of maximal aerobic power. Freely chosen cadence (FCC) was also determined, also at 65% of maximal aerobic power, from five randomised three minute sessions at 50, 65, 80, 95, and 110 rpm. The integrated electromyographic signal of the vastus lateralis and gastrocnemius lateralis muscles was recorded during MVC and the cycle task. RESULTS: The FCC decreased significantly (p<0.01) from P1 (87.4 rpm) to P2 (68.6 rpm), towards the energetically optimal cadence. The latter did not vary significantly during the cycle task. MVC of the vastus lateralis and gastrocnemius lateralis decreased significantly (p<0.01) between P1 and P2 (by 13.5% and 9.6% respectively). The results indicate that muscle activation at constant power was not minimised at specific cadences. Only the gastrocnemius lateralis muscle was affected by a two hour cycling task (especially at 95 and 110 rpm), whereas vastus lateralis remained stable. CONCLUSION: The decrease in FCC observed at the end of the cycle task may be due to changes in the muscle fibre recruitment pattern with increasing exercise duration and cadence.