Aspects biologiques des interactions de l’exercice et de la récupération

Subject

The use of Fourier transform infrared spectrometry technique (FT-IR) as a pitch technique of the biological control of short and intense exercises close to those of Rugby matches.

Material and method

In reference to 28 rugbymen of international level, the biological results of three short and intense exercises and two periods of recovery were analyzed by TF-IR. The exercises are: (1) sprints; (2) 12 × 20 m of swerve running; (3) 6 × 30 s of shuttle run.

Results

Lactate, glucose, urea, and to a lesser degree, triglycerides showed a significant evolution. If the evolution of the two first was in conformity with the literature, the increase of urea probably results from the activation of the purins–nucleotides cycle, whereas the evolution of triglycerides is explained by their probable muscular use during periods of active recovery. Among proteins related to the healthy sportsman, only haptoglobin presents a significant variation difficult to explain whereas CRP, orosomucoid and immunoglobulins A, G and M remain close to their rest values.

Conclusion

With the use of FT-IR technique, it is possible to intervene directly on the pitches of the sporting practice to control the biological incidences and to adjust the loads individually. It is also possible to detect inflammatory and immunological problems related to the biomechanical and physiological stresses.     

Prévention des lésions de l’appareil locomoteur liées à la pratique de l’athlétisme sur piste. Revue des données épidémiologiques

Objectives

Sports injuries have an important impact on the sport and in daily life. Although athletics is known and performed on five continents, few is known about epidemiological data such as frequency, incidence, diagnosis or risk factors of injuries in athletics. In this context, consideration on strategies of sports injury prevention in athletics should be conducted.

Current knowledge

Sports injury surveillance by epidemiological studies is a preliminary step necessary in the clinical research on sports injury prevention. This is permitted by an agreed and validated methodolgy. Currently, the musculoskeletal lesions related to the track and field practice are common. The great diversity of these lesions reflects the diversity of disciplines, the constraints are different between the explosive disciplines (sprints, hurdles, jumps, throws) and endurance disciplines (middle and long distance). There was a predominance of lesions of thigh and hamstrings in the disciplines of sprint/hurdles, the Achilles tendon in jumps and sprints/hurdles, and chronic knee injuries and stress fractures in middle-distance.

Conclusion

Preventive measures which target the most frequent pathologies should be introduced. However, these data appear insufficient to fully understand the specific injury according to disciplines, and to understand the risk factors and injury mechanisms. Therefore, prospective epidemiological studies, and studies focused on specific populations or pathologies, are needed to improve strategies for the prevention of injuries in track and field.     

Exploration détaillée des composantes de la glycorégulation chez des sportifs sujets aux hypoglycémies d’effort. Intérêt de l’oral minimal model

Context

Exercise hypoglycaemia (EH) is a very common yet little studied condition. It occurs in subjects with high values of insulin sensitivity (S_I) and glucose effectiveness (S_G), and is mainly triggered by dietary errors, over-training, or special circumstances (exposure to unusual temperatures, altitude, disruption of circadian rhythms).

Methods and results

We showed that S_I and S_G can be calculated from test meals by mathematical modelling (oral minimal model), whereas in athletes “surrogates” of S_I (HOMA, QUICKI, etc.) are misleading (not applicable in this area of high insulin sensitivity). These meals can also provide a comprehensive picture of the components of insulin secretion, which makes this exploration more informative. We studied the results obtained by this method in 19 athletes complaining of EH compared to 58 matched athletes not complaining from this problem. We observed higher values of S_I (P < 0.05) and S_G (P < 0.03), but overall, insulin secretion Φ_oral was similar. However, one of the components of insulin secretion, β-cell glucose sensitivity, is higher on the average (P < 0.04) because in 30% of cases it remains above the normal range for athletes, while remaining in the range for a normal population. Therefore, overall tolerance to carbohydrates (product Φ_oral × S_I) is higher (+58% P < 0.04).

Conclusion

Thus, these subjects have a powerful carbohydrate disposal, which is incompletely compensated by the expected homeostatic decrease in insulin secretion, especially with regard to β-cell glucose sensitivity.     

Profil musculaire isocinétique du genou chez des sprinteurs et des sauteurs de haut niveau

Purpose

To study the isokinetic knee strength profile in elite sprinters and jumpers with recurrent hamstring injuries.

Method

A group of eight elite athletes including sprinters and jumpers with previous hamstring injuries were compared to a control group of non-injured players (n = 8). The concentric isokinetic knee flexion and extension strength was assessed at 60, 120 and 180 °/s using a Biodex^® System 3 dynamometer.

Results

There were no significant differences for any of the isokinetic variables comparing the injured and the non-injured athletes except for the hamstring to quadriceps ratio, which is lower in the control group. No significant difference was observed between the dominant and the non-dominant leg for the two groups.

Conclusion

Isokinetic muscle strength testing allows to detect the existence of a strength deficit after a hamstring injury during sports practice. Additional eccentric tests may be required to identify these cases.