The effect of a one-leg cycling aerobic training program during the rehabilitation period in soccer players with anterior cruciate ligament reconstruction.

OBJECTIVES: To examine cardiorespiratory fitness, resting cardiac parameters, and muscle oxygenation changes in soccer players having undergone anterior cruciate ligament reconstruction and to assess the benefits of a one-leg cycling (OLC) aerobic training program performed during the rehabilitation period. DESIGN: Randomized clinical trial. SETTING: Outpatient clinic, primary care. PATIENTS: Twenty-four, male, regional-level soccer players who had undergone surgical reconstruction of the anterior cruciate ligament of the knee. INTERVENTION: Patients were randomly assigned to 1 of 2 groups: either an individualized OLC aerobic training program with the untreated leg plus a rehabilitation program (training group, TG) or a group that received the same rehabilitation program but without aerobic training (control group, CG). MAIN OUTCOME MEASURES: Outcome measurements assessed before (T1) and after 6 weeks (T2) were stroke volume (SV) and end-diastolic volume (EDV) during resting cardiac echography measurement and peak work rate (W(peak)), peak O(2) uptake (VO(2)peak), peak minute ventilation (VE(peak)), first and second ventilatory threshold (VT1 and VT2), leg muscle oxygenation (LMO(2)), and blood volume (LMBV) during maximal graded tests performed with the untreated leg. RESULTS: At T1, there was no significant difference between TG and CG. For TG, W(peak), VE(peak), VT1, VT2, LMO(2), and LMBV at each work rate were significantly higher at T2 than at T1. For CG, W(peak), VO(2)peak, VE(peak), VT2, SV, and EDV decreased significantly at T2 in comparison with T1. CONCLUSIONS: One-leg cycling training could involve specific adaptations in comparison to a standard rehabilitation program. Moreover, OLC training during rehabilitation seems to stop the effects of hypoactivity.

Effect of one-leg cycling aerobic training in amateur soccer players after anterior cruciate ligament reconstruction.

OBJECTIVE: To examine before and after 6 wks of rehabilitation, the cardiorespiratory fitness, and resting cardiac parameter changes in soccer players having undergone anterior cruciate ligament reconstruction and to assess the benefits of a one leg cycling aerobic training program with the nonsurgical leg during the rehabilitation period. DESIGN: Twenty-four amateur soccer players took part in this study. The subjects were then randomly assigned to one of two groups--either an individualized one leg cycling aerobic program (training group) or without cardiorespiratory training (control group). The initial evaluation (T1) was carried out the first day of rehabilitation and the final evaluation (T2) within 42 days. Both consisted of resting cardiac echography measurement and maximal graded tests performed with the nonsurgical leg. RESULTS: For training group, peak power output, peak minute ventilation, the first (VT1), and second (VT2) ventilatory threshold values were significantly (P < 0.05) higher at T2 than at T1 (+13%, +10%, +7%, and +11%, respectively). For control group, peak power output, peak oxygen uptake, peak minute ventilation, and VT2 values decreased significantly at T2 in comparison with T1(-10%, -10%, -12%, and -11%, respectively). After hospitalization, significant reductions in end diastolic volume (T1, 116 +/- 17 ml; T2, 97 +/- 16 ml; P < 0.05) and stroke volume (T1, 75 +/- 14 ml; T2, 59 +/- 12 ml; P < 0.05) were also observed. For training group, the cardiac parameters were similar between T1 and T2. CONCLUSION: These results suggest that one leg cycling training during the rehabilitation seems to be an adapted method to stop the effects of hypoactivity.

Influence of successive bouts of fatiguing exercise on perceptual and physiological markers during an incremental exercise test.

The purpose of this study was to examine the effects of a succession of fatiguing stages, on ratings of perceived exertion (RPE) and estimated time limits (ETL) during an incremental exercise test. Twenty-seven cyclists performed a continuous incremental test and a discontinuous test with randomized workloads. A linear mixed model was used to compare the RPE, ETL, respiratory gas, heart rate, and blood data obtained during the two exercise tests. RPE and ETL were not significantly different between the tests. Ventilation, breathing frequency, heart rate, and blood lactate concentration were significantly higher during the last incremental test workloads. In conclusion, although the incremental exercise test generated higher cardiorespiratory and muscular workloads than observed during the randomized exercise test, most likely due to a greater fatiguing process, these higher workloads did not influence the perceptual response.

One-leg cycling versus arm cranking: which is most appropriate for physical conditioning after knee surgery?

OBJECTIVE: To compare the cardiorespiratory responses, blood lactate concentration and perceived exertion between 1-leg cycling and arm cranking. DESIGN: Comparison of exercise modalities. SETTING: Hospital. PARTICIPANTS: Fourteen men who had undergone knee surgery were evaluated during rehabilitation. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Each patient performed 2 maximal graded tests: 1-leg cycling and arm cranking exercise, with a 7-day interval. Respiratory gas exchange, heart rate, blood lactate concentration, and the ratings of perceived exertion (RPE) were measured. RESULTS: Peak power output, peak minute ventilation, peak oxygen uptake (Vo(2)peak), and peak heart rate did not differ significantly between 1-leg cycling and arm cranking. The first and second ventilatory thresholds occurred at above 40% and 72% of Vo(2)peak, respectively, in both tests. The maximal lactate concentrations and the RPE values were significantly higher during arm cranking (+10%, +12%, respectively, P<.05) compared with corresponding 1-leg cycling values. CONCLUSIONS: The maximal cardiorespiratory values were not different between arm cranking and 1-leg cycling. However, the RPE and blood lactate concentration were lower when the exercise was performed with the lower limb. Thus 1-leg cycling may be more easily tolerated than arm cranking by patients participating in aerobic conditioning after knee surgery.

Effects of knee surgery on cardiac function in soccer players.

OBJECTIVE: To evaluate the effects of knee surgery on hematocrit and hemoglobin concentration and on resting cardiac parameters as measured by echocardiography. DESIGN: Ten soccer players who underwent knee surgery were evaluated before (T1) and after (T2) hospitalization within a 7-day interval. RESULTS: After hospitalization, end diastolic volume and stroke volume were significantly reduced (P < 0.05) by 14 and 22%, respectively. Despite a significant increase in resting heart rate (T1: 68 +/- 3.3 beats/ min, T2: 72 +/- 3.1 beats/min, P < 0.05), cardiac output was significantly decreased (T1: 4.89 +/- 0.56 liters/min; 3.95 +/- 0.62 liters/min, P < 0.05). The ejection fraction was 65% at T1 and fell to 58% at T2 (P < 0.05). After hospitalization, significant decreases in hemoglobin concentration and hematocrit were observed, suggesting a fall in blood volume. CONCLUSION: In soccer players, knee surgery leads to resting cardiac deconditioning, which is characterized by a significant reduction in stroke volume.

Related trends in locomotor and respiratory muscle oxygenation during exercise.

PURPOSE: We investigated the potential effect of respiratory muscle work on leg muscle oxygenation without artificial intervention in non-endurance-trained young subjects and searched for the range of intensity when this effect could occur. METHODS: We simultaneously monitored accessory respiratory and leg muscle oxygenation patterns with near-infrared spectroscopy (NIRS) in 15 healthy young men performing maximal incremental exercise on a cycle ergometer. Pulmonary gas exchange was measured. The respiratory compensation point (RCP) was determined. Oxygenation (RMO2) and blood volume (RMBV) of the serratus anterior (accessory respiratory muscle) and of the vastus lateralis (LegO2 and LegBV) were monitored with NIRS. The breakdown point of accessory respiratory muscle oxygenation (BPRMO2) and the accelerated (BP1LegO2) and attenuated fall (BP2LegO2) in leg muscle oxygenation were detected. RESULTS: BPRMO2 occurred at approximately 85% .VO2max and was related to RCP (r = 0.88, P < 0.001). BP2LegO2 appeared at approximately 83% .VO2max and was related to RCP (r = 0.57, P < 0.05) and with BPRMO2 (r = 0.64, P = 0.01). From BP2LegO2 to maximal exercise, LegBV was significantly reduced (P < 0.05). CONCLUSION: In active subjects exercising at heavy exercise intensities, we observed that the appearance of the accelerated drop in accessory respiratory muscle oxygenation-associated with high ventilatory level-was related with the attenuated fall in leg muscle oxygenation detected with near-infrared spectroscopy. This suggests that the high oxygen requirement of respiratory muscle leads to limited oxygen use by locomotor muscles as demonstrated in endurance-trained subjects. The phenomenon observed was associated with reduced leg blood volume, supporting the occurrence of leg vasoconstriction. These events appeared not only at maximal exercise but onward above the respiratory compensation point.

Heart rate variability before and after knee surgery in amateur soccer players.

OBJECTIVE: To analyze the consequences on heart rate variability (HRV) of a hospitalization period due to surgery of the knee in sportsmen. PATIENTS: Ten soccer players who had undergone knee surgery took part in this study. DESIGN: HRV was measured before and after hospitalization within a 7-day interval. RESULTS: After the hospitalization phase, heart rate at rest increased significantly (3 beats/minute). A significant decrease of 7% in the cardiac inter beat interval (R-R interval), P < 0.05 and a 66% decrease in total power spectral density: -66%, P < 0.05 were observed. The disturbance of the autonomic nervous system could be due to a variation in cardiac vagal activity resulting in a 64% decrease in the high frequencies (P < 0.05). This variation was not associated with a modification in normalized markers (LFn.u., HFn.u.) and LF/HF ratio (P > 0.05). CONCLUSION: In sportsmen, a hospitalization period led to an increase in resting heart rate and was associated with a disturbance of the autonomic nervous system.

O2 arterial desaturation in endurance athletes increases muscle deoxygenation.

PURPOSE: The aim of this study was to compare the muscle deoxygenation measured by near infrared spectroscopy in endurance athletes who presented or not with exercise-induced hypoxemia (EIH) during a maximal incremental test in normoxic conditions. METHODS: Nineteen male endurance sportsmen performed an incremental test on a cycle ergometer to determine maximal oxygen consumption (VO2max) and the corresponding power output (P(max)). Arterial O2 saturation (SaO2) was measured noninvasively with a pulse oxymeter at the earlobe to detect EIH, which was defined as a drop in SaO2 > 4% between rest and the end of the exercise. Muscle deoxygenation of the right vastus lateralis was monitored by near infrared spectroscopy and was expressed in percentage according to the ischemia-hyperemia scale. RESULTS: Ten athletes exhibited arterial hypoxemia (EIH group) and the nine others were nonhypoxemic (NEIH group). Training volume, competition level, VO2max, Pmax, and lactate concentration were similar in the two groups. Nevertheless, muscle deoxygenation at the end of the exercise was significantly greater in the EIH group (P < 0.05). CONCLUSION: Greater muscle deoxygenation at maximal exercise in hypoxemic athletes seems to be due, at least in part, to reduced oxygen delivery--that is, exercise-induced hypoxemia--to working muscle added to the metabolic demand. In addition, our finding is also consistent with the hypothesis of greater muscle oxygen extraction in order to counteract reduced O2 availability.