Rapid recovery of performance is important for elite athletes engaged in intermittent exercise that involves periods of intense exercise interspersed with short recovery periods (eg, martial arts, ice hockey, field sports). Optimizing training recovery may also be beneficial for performing successive bouts of training or competition over a season without associated fatigue or overtraining effects.
The inability to repeat the same level of performance in short-duration exercise is frequently attributed to peripheral fatigue involving metabolite accumulation and muscle damage1,2
resulting from mechanical stress, imbalances in muscle cell homeostasis, or local inflammation from exercise.3
Indeed, the response of different muscle enzymes (mainly creatine kinase [CK] and lactate dehydrogenase [LDH]) has received researchers' attention because strenuous exercise induces muscle cell structural damage, which results in increased plasma concentrations of muscle enzymes such as CK and LDH.4
The efflux of CK and LDH proteins from muscle may be attributed to increased permeability of the plasma membrane or intramuscular vasculature (or both).5
Thus, a reduction in these markers has been proposed as an indicator of recovery after strenuous exercise that induces muscle damage.6
To optimize recovery, various techniques have been suggested to accelerate the clearance of muscular damage or metabolite accumulations. Usually, these techniques focus on local fatigue. Their main goal is to treat fatigue by directly applying the recovery method to the working muscles (eg, electromyostimulation, local cryotherapy, or cold-water immersion). This approach showed positive results after muscle damage by reducing local inflammation, especially when cold modalities were used.7
However, results on peripheral fatigue from metabolite accumulation are inconclusive, probably because the metabolic byproducts are released into the blood. From these findings, a change in the recovery approach from a local treatment to a systemic view was necessary. One possible way to achieve this goal is to improve the peripheral circulation and the venous return by stimulating total blood flow. In athletes, several techniques have been proposed to achieve this result. Of these, active recovery,8,9
contrast water therapy,10
low-level laser therapy,12
and low-frequency electromyostimulation13
have been investigated and compared with passive recovery (PAS).6,14
The results of these studies provide no definitive consensus on the ability to improve explosive strength and anaerobic capacity performance or clear muscle damage markers after exercise.15–17
Lattier et al18
showed no difference in neuromuscular function and maximal test performance after a recovery intervention using blood-flow stimulation from electromyostimulation compared with PAS or active recovery. Based on these observations, several authors concluded that the effects of these techniques are minimal, especially on performance. However, researchers13,19
have hypothesized that this lack of effect could also be associated with the technique, the device used, or the localization of the electric stimulation (eg, systemic treatment [calf] versus local treatment [quadriceps]), suggesting that the blood flow and, more particularly, the venous return may not be effectively increased. Accordingly, Martin et al13
recommended optimizing the electric stimulation to better approximate the physiologic contraction of the muscle; a new way of using an electric muscle stimulator on the calf muscles could provide interesting results. This systemic approach is based on results showing that total blood flow can be efficiently stimulated by intensifying the pumping action associated with calf muscle contractions from techniques such as electromyostimulation, cuff inflation, or walking.20
Indeed, these muscles, which have been termed the “peripheral venous heart,” “calf muscle pump,” and “musculovenous pump,” were responsible for 80% of the venous return21–23
and considered a second heart. A low-intensity, repetitive mechanical contraction-relaxation muscle cycle may increase local and total blood flow, translocation, and removal of metabolites and reduce intracellular fluid volume.24
However, using electric muscle stimulation to increase blood flow for exercise recovery has been ineffective despite the emergence of new devices that significantly improved total blood flow and venous return.25–29
Therefore, we hypothesized that such a device applied to the calf muscles could result in faster restoration in performance and reduce the amount of muscle damage markers after fatiguing exercise.
The purpose of our study was to investigate the effectiveness of muscle stimulation using the VEINOPLUS unit (Ad Rem Technology, Paris, France) on explosive strength and 30-second all-out performance and CK and LDH recovery profiles in professional soccer players after exhaustive intermittent exercise. We proposed that use of the VEINOPLUS would result in better restoration of anaerobic performance than passive recovery.