[Athletes with exercise-related pain at the medial side of the lower leg]. / Sporters met inspanningsgerelateerde pijn aan de mediale zijde van het onderbeen.

Two patients were diagnosed with exercise-related pain at the medial side of the lower leg. The first patient, an 18-year-old woman who had expanded her athletic activities extensively, had developed pain at the inner side of the distal third portion of the left lower leg. She showed over-pronation of the ankle during running. A 3-phase bone scintigram revealed diffuse uptake of the tracer covering a large portion of the medial tibia margin. Based on this evidence, a diagnosis of periostalgia was made. She recovered after a period of relative calf massages and used insoles. The second patient was a 28-year-old male endurance runner who developed pain at the medial shin after intensifying his training regimen. The periods without pain during running became increasingly shorter, and the medial side of the lower leg became sore and tense. Intracompartmental pressure measurements indicated exercise-related posterior deep compartment syndrome of the calf. The patient recovered after fasciotomy. In athletes, exercise-related symptoms of the medial side of the lower leg can be usually attributed to the tibial periosteum or tendons of the deep calfmusculature, tibial stress reaction or fracture, or a compartment syndrome of the deep calf. Surgery is indicated for chronic compartment syndrome, but conservative therapy provides favourable outcomes in the other types of disorders. The optimal conservative therapeutic approach is unknown, but it is advisable to temporary reduce symptom-provoking athletic activity and modify any risk factors present. Ankle over-pronation during running is considered a very relevant intrinsic risk factor.

The maximal lactate steady state in elite endurance athletes.

The upper limit of blood lactate resulting in a lactate steady state during prolonged exercise is called the maximal lactate steady state (MLSS). The purpose of this study was to investigate the lactate response to steady-state exercise during a field test in elite endurance athletes. Plasma lactate levels were assessed in 13 elite triathletes and 13 elite cyclists (mean +/- SD; age 23.7 +/- 5.1 yr; HT 180.2 +/- 6.3 cm; WT 70.3 +/- 5.9 kg; VO2 max 68 +/- 3.7 ml/min/kg) during a 40 km-long time trial on a bicycle (4 km course x 10 laps). The steady state was demonstrated by monitoring the heart rate and timing every course run. The lactate levels were expected to correspond to MLSS. The mean level of lactate during the time trial was 7.4 +/- 2.5 mmol/l. Five athletes maintained plasma lactate levels which exceeded 10 mmol/l or more for almost 1 h. The large value of individual variability was conspicuous (range 3.2-12.2 mmol/l). These values exceeded all previous reported levels for MLSS from other investigators. Our observations are important in sport medical practice since the different lactate responses to exercise are used as parameters in training management.

[Long-term intensive athletic training; few adverse effects on later physical health]. / Langdurige intensieve fysieke sportbeoefening: weinig nadelige late gevolgen voor de gezondheid.

In general, physical activity benefits health. However, long-term intensive physical training may have detrimental effects on the health of some individuals. In cyclists, changes in the femoral arteries may occur leading to stenoses that are manifested in claudication type symptoms. Some endurance athletes may experience atrial fibrillations that are possibly related to long-term physical training. Older athletes only have an increased risk of osteoarthritis in joints that have suffered injuries. Menstrual disturbances and premature osteoporosis may occur in women as a consequence of intensive physical training. However, the risk for these adverse consequences of long-term physical training is small.

Chronic deep posterior compartment syndrome of the leg in athletes: postoperative results of fasciotomy.

The present study evaluates the efficacy of two treatment regimens in individuals possibly suffering from chronic exercise induced compartment syndrome (CECS) of the deep posterior compartment of the leg. We hypothesised that the current method of fasciotomy of the deep posterior compartment of the leg is a procedure with a limited success rate. Dynamic intra-compartmental pressure measurements were applied to 46 patients that had symptomatology of a posterior CECS. Only those patients that met predefined pressure criteria, the "high-pressure group" (27 patients), were offered surgical treatment in the form of fasciotomy. The other 19 patients, "low-pressure group", received conservative treatment, consisting of inlays and physiotherapy. In addition, these patients were examined more closely in order to exclude different pathology. Efficacy of both approaches was evaluated by a questionnaire after a mean three-year follow-up. Fifty-two percent of the high-pressure group judged their operation successful, whereas 48 % did not. The majority of the low-pressure group (84 %) was free of symptoms, after conservative treatment as well as following treatment of other pathology. The present study shows that the success rate of patients surgically treated for posterior CECS is relatively low (52 %). The established cut-off points for the compartment pressure to deselect patients for an operation are justified based on the long-term success rate of the low-pressure group.

The effect of endurance training on the ventilatory response to exercise in elite cyclists.

The purpose of this study was to investigate the effects of endurance training on the ventilatory response to acute incremental exercise in elite cyclists. Fifteen male elite cyclists [mean (SD) age 24.3 (3.3) years, height 179 (6) cm, body mass 71.1 (7.6) kg, maximal oxygen consumption (VO2max) 69 (7) ml x min(-1) x kg(-1)] underwent two exercise tests on a cycle ergometer. The first test was assessed in December, 6 weeks before the beginning of the cycling season. The second test was performed in June, in the middle of the season. During this period the subjects were expected to be in a highly endurance-trained state. The ventilatory response was assessed during an incremental exercise test (20 W x min(-1)). Oxygen consumption (VO2), carbon dioxide production (VCO2), minute ventilation (VE), and heart rate (HR) were assessed at the following points during the test: at workloads of 200 W, 250 W, 300 W, 350 W, 400 W and at the subject's maximal workload, at a respiratory exchange ratio (R) of 1, and at the ventilatory threshold (Th(vent)) determined using the V-slope-method. Post-training, the mean (SD) VO2max was increased from the pre-training level of 69 (7) ml x min(-1) x kg(-1) (range 61.4-78.6) to 78 (6) ml x min(-1) x kg(-1) (range 70.5-86.3). The mean post-training VO2 was significantly higher than the pre training value (P < 0.01) at all work rates, at Th(vent) and at R = 1. VO2 was also higher at all work rates except for 200 W and 250 W. VE was significantly higher at Th(vent) and R = 1. Training had no effect on HR at all workloads examined. An explanation for the higher VO2 cost for the same work rate may be that in the endurance-trained state, the adaptation to an exercise stimulus with higher intensity is faster than for the less-trained state. Another explanation may be that at the same work rate, in the less-endurance-trained state power is generated using a significantly higher anaerobic input. The results of this study suggest the following practical recommendations for training management in elite cyclists: (1) the VO2 for a subject at the same work rate may be an indicator of the endurance-trained state (i.e., the higher the VO2, the higher the endurance-trained capacity), and (2) the need for multiple exercise tests for determining the HR at Th(vent) during a cycling season is doubtful since at Th(vent) this parameter does not differ much following endurance training.

The plasma lactate response to exercise and endurance performance: relationships in elite triathletes.

The lactate response to exercise has been studied thoroughly during the last decades and it has been described using a variety of terms and definitions. Numerous investigations observed close relationships between the lactate response and endurance performance. The main question in this study was which of the various lactate responses during incremental exercise described in the literature was the best indicator of endurance performance. The plasma lactate response (PLR) was assessed during an incremental exercise test on 13 male elite triathletes (age 25.5+/-5.8 yrs; HT 179.7+/-5.4 cm; WT 71.3+/-4.7 kg) on a bicycle ergometer. The load was started at 2.5 W/kg and increased by 40 W every 4 min. We evaluated the following PLR-parameters: the workloads at the fixed lactate levels of 2, 3, 4, 5, 6, 7, and 8 mmol/l which were assessed by extrapolation from a workload-lactate-heart rate curve (P2, P3, P4, P5, P6, P7, P8 respectively), the lactate threshold which was defined as the workload at the point at which a non-linear increase of blood lactate occurred (Plt), and the workload at the lactate level that was 1 mmol/l above the baseline (P + 1). Four to seven weeks after the laboratory test, heart rate and lactate levels were assessed during a 40-km long time trial on a bicycle. Two parameters were considered as indicative of athletic performance: the road racing time (Tt), and the workload extrapolated from the workload-lactate-heart rate curve at the heart rate and lactate levels observed during the time trial (Pt). Only P2 showed a significant correlation with Tt (r=-0.65; p < 0.05; se = 72.5 s). Multiple regression analysis with the anthropometric parameters height and weight as additional independent parameters did not change the predictive value. We concluded that for predicting the cycling performance of similarly well-trained subjects the predictive value of PLR is negligible.

Relationships between testosterone, cortisol and performance in professional cyclists.

In the literature the use of plasma levels of cortisol and the testosterone and testosterone: cortisol ratio for training management is encouraged. Decreased levels of testosterone and increased levels of cortisol are suggested to be indicative for a disturbance in the anabolic-catabolic balance, which may express itself in decreased performance. The purpose of the study was to examine if the acute hormonal response to a bout of exercise and the resting levels of testosterone, luteinizing hormone (LH) and cortisol are correlated to performance in cyclists. In addition, the effect of training on this correlation was studied. Ten professional cyclists participated and measurements took place before and after a defined period of training. Maximum workload (Pmax), determined on a cycle-ergometer with a slowly increasing protocol, increased by 30 watt (p < 0.001). Workload at a lactate level of 4 mmol/l (P4) increased by 18 watt (p < 0.05). Post training, resting testosterone levels decreased from 28.8 +/- 74 nmol/l to 24.6 +/- 90 nmol/l (p < 0.05). Resting cortisol levels increased from 272 +/- 110 nmol/l pre training to 379 +/- 242 nmol/l post training (p < 0.05). These results indicate an increased catabolic state. The acute hormonal response and the resting levels of LH were not changed post training. The resting levels of testosterone and cortisol and the acute response to exercise showed no correlation with performance pre and post training. In spite of an increased catabolic state post training there was an increase in performance. These results suggest that in endurance trained cyclists, decreased testosterone levels, increased cortisol levels and a decreased testosterone: cortisol ratio does not automatically lead to a decrease in performance or a state of overtraining.

The ventilatory threshold, heart rate, and endurance performance: relationships in elite cyclists.

The purpose of this study was to investigate the validity of the ventilatory response during incremental exercise as indication of endurance performance during prolonged high-intensity exercise under field test conditions in elite cyclists. The ventilatory threshold (VT) was assessed in 14 male elite cyclists (age 22.4+/-3.4 years, height 181+/-6 cm, weight 69.2+/-6.8 kg, VO2max 69+/-7 ml x min(-1) x kg(-1)) during an incremental exercise test (20 W x min(-1)). Heart rate and oxygen uptake were assessed at the following ventilatory parameters: 1. Steeper increase of VCO2 as compared to VO2 (V-slope-method); 2. Respiratory exchange ratio (RQ)=0.95 and 1.00; 3. VE/VO2 increase without a concomitant VE/VCO2 (VE/VO2 method). Three weeks following the laboratory tests, the ability to maintain high-intensity exercise was determined during a 40 km time trial on a bicycle. During this time trial the mean heart rate (HR(TT)) and the road racing time (TT) were assessed. The V-slope-method and the VE/VO2 method showed significant correlations with TT (V-slope: r = -0.82; p<0.001; 90% interval of confidence = +/-82 sec; VE/VO2: r=-0.81; p<0.01; 90% interval of confidence = +/-81 sec). Heart rate at the ventilatory parameters and at the maximum heart rate (HRmax) showed significant correlations with HR(TT). The V-slope-method is the preferred method to predict heart rate during prolonged high-intensity exercise (r=0.93; p<0.0001; 90% interval of confidence: +/-4.8 beats x min(-1)). For predicting heart rate during prolonged high-intensity exercise using an incremental exercise test (20 W x min(-1)), without the knowledge of ventilatory parameters, we recommend using the regression formula: H(TT)=0.84 x Hmax + 14.3 beats x min(-1) (r=0.85; p<0.001).