Gaëlle Deley

Comparison of low-frequency electrical myostimulation and conventional aerobic exercise training in patients with chronic heart failure.

Background Physical training is recommended as an efficient therapy in patients with chronic heart failure (CHF). Low-frequency electrical myostimulation (EMS) has recently been suggested as a good alternative to conventional aerobic training. The aim of this study was to compare the effects of EMS and conventional exercise training in patients with moderate to severe CHF. Methods Twenty-four patients with stable CHF (56.7±7.3 years, New York Heart Association grades II and III) underwent 5 weeks of exercise training, 5h a week, using EMS (n=12) or conventional (n=12) training programmes. At baseline and after the training period, patients performed a symptom-limited cardiopulmonary test, a 6-min and a 200-m walk exercises and an evaluation of maximal knee extensor strength. Results Oxygen uptake (VO2) and workload at the end of exercise (peak values) and at ventilatory threshold increased after EMS (P ≤ 0.05) and conventional exercise (P<0.05) training programmes. The slope of the relationship between VO2 and workload was reduced after EMS (P<0.05). The time to recover half of peak VO2 decreased irrespective of the training programme (P<0.001). EMS and conventional exercise training programmes also increased the maximal knee extensor strength (P<0.05), the distance walked in 6 min (P<0.01) and decreased the time elapsed to cover 200 m (P<0.05). These improvements were not statistically different between EMS and conventional exercise. Conclusion In patients with moderate to severe CHF, 5 weeks of EMS and conventional exercise training produce similar improvements to exercise capacity and muscle performance.

Effects of a one-year exercise training program in adults over 70 years old: a study with a control group

Background and aims: Exercise training is known to improve exercise tolerance in elderly subjects. Therefore the present study aimed at investigating the effects of one year of combined endurance and resistance training in healthy older people. Methods: After baseline evaluation, subjects were assigned to either the training group (n=24, age 77.2±3.6) or the control group (n=16, age 76.1±4.8). Subjects in the control group did not change anything in their everyday activities, whereas subjects in the training group underwent moderately intensive combined exercise training, 3 hours a week over the course of one year. Breath-by-breath oxygen uptake and heart rate were measured at each workload during the symptom-limited cardiopulmonary exercise test. Performance on the 6-minute (6-MWT) and 200-meter (200-MWT) walk tests was registered and maximal strength was measured on knee extensor and plantar flexor muscles. Results: After training, oxygen uptake was significantly increased, both at the ventilatory threshold (+11.6%, p<0.01) and at the end of exercise (+14.8%, p<0.001). The distance walked in 6 min (+10%, p<0.001), the time required to cover 200 m (−7.3%, p<0.001) and the maximal muscle strength (+15.2% and +17.4% for knee extensors and plantar flexors respectively, p<0.05) also improved after training. All these parameters had not significantly changed in the control group after the one-year period. Conclusions: The results of the present study show that one year of combined exercise training is well-tolerated and improves aerobic capacity, performance on field tests and muscle strength in healthy subjects over 70 years old.

Arterial Baroreflex Control of Cardiac Vagal Outflow in Older Individuals Can Be Enhanced by Aerobic Exercise Training

Maintained cardiac vagal function is critical to cardiovascular health in human aging. Aerobic exercise training has been considered an attractive intervention to increase cardiovagal baroreflex function; however, the data are equivocal. Moreover, if regular exercise does reverse the age-related decline in cardiovagal baroreflex function, it is unknown how this might be achieved. Therefore, we assessed the effects of a 6-month aerobic training program on baroreflex gain and its mechanical and neural components in older individuals (5 women and 7 men, aged 55 to 71 years). We assessed baroreflex function using pharmacological pressure changes (bolus nitroprusside followed by bolus phenylephrine) and estimated the integrated gain (&Dgr;R-R interval/&Dgr; systolic blood pressure) and mechanical (&Dgr; diameter/&Dgr; pressure) and neural (&Dgr;R-R interval/&Dgr; diameter) components via measurements of carotid artery diameter in previously sedentary older individuals before and after 6 months of aerobic training. There was a significant 26% increase in baroreflex gain that was directly related to the amount of exercise performed and that was derived mainly from an increase in the neural component of the arterial baroreflex (P<0.05). We did find changes in the mechanical component, but unlike integrated gain and the neural component, these were not related to the magnitude of the exercise stimulus. These results suggest that exercise training can have a powerful effect on cardiovagal baroreflex function, but a sufficient stimulus is necessary to produce the effect. Moreover, adaptations in the afferent-efferent baroreflex control of cardiac vagal outflow may be crucial for the improvement in arterial baroreflex function in older humans.

Feasibility and efficacy of progressive electrostimulation strength training for competitive tennis players.

Maffiuletti, NA, Bramanti, J, Jubeau, M, Bizzini, M, Deley, G, and Cometti, G. Feasibility and efficacy of progressive electrostimulation strength training for competitive tennis players. J Strength Cond Res 23(2): 677-682, 2009-The purpose of this preliminary study was to show the feasibility of electrostimulation (ES) strength exercise incorporated into tennis sessions during the preparatory season of competitive players, and its impact on anaerobic performance. Twelve tennis players (5 men, 7 women) completed 9 sessions of quadriceps ES (duration: 16 minutes; frequency: 85 Hz; on-off ratio: 5.25-25 seconds) during 3 weeks. The ES sessions were integrated into tennis training sessions. Subjects were baseline tested and retested 1 (week 4), 2 (week 5), 3 (week 6), and 4 weeks (week 7) after the ES training program for maximal quadriceps strength, vertical jump height, and shuttle sprint time. Participants were able to progressively increase ES current amplitude and evoked force throughout the 9 training sessions, with an optimal treatment compliance of 100%. Maximal quadriceps strength significantly increased during the entire duration of the experiment (p < 0.001). Countermovement jump height at week 5 (+5.3%) and week 6 (+6.4%) was significantly higher than at baseline (p < 0.05). In addition, 2 × 10-m sprint time at week 6 was significantly shorter (−3.3%; p = 0.004) compared with pretraining. The 3-week ES strength training program was successfully incorporated into preseason tennis training with a linear progression in all training parameters. Throughout the study period, a delayed enhancement of anaerobic power and stretch-shortening cycle performance was observed. Progressive ES strength training may be safely included in the early tennis season and can lead to improvements in the anaerobic performance of men and women players.

Does electrical stimulation enhance post-exercise performance recovery?

Elite sport requires high-volume and high-intensity training that inevitably induces neuromuscular fatigue detrimental for physical performance. Improving recovery processes is, therefore, fundamental and to this, a wide variety of recovery modalities could be proposed. Among them, neuromuscular electrical stimulation is largely adopted particularly by endurance-type and team sport athletes. This type of solicitation, when used with low stimulation frequencies, induces contractions of short duration and low intensity comparable to active recovery. This might be of interest to favour muscle blood flow and therefore metabolites washout to accelerate recovery kinetics during and after fatiguing exercises, training sessions or competition. However, although electrical stimulation is often used for recovery, limited evidence exists regarding its effects for an improvement of most physiological variables or reduced subjective rating of muscle soreness. Therefore, the main aim of this brief review is to present recent results from the literature to clarify the effectiveness of electrical stimulation as a recovery modality.

DO LOW-FREQUENCY ELECTRICAL MYOSTIMULATION AND AEROBIC TRAINING SIMILARLY IMPROVE PERFORMANCE IN CHRONIC HEART FAILURE PATIENTS WITH DIFFERENT EXERCISE CAPACITIES?

OBJECTIVE To confirm that electrical myostimulation is a good alternative to conventional aerobic training in patients with chronic heart failure and to compare the effects of both training programmes in patients with different exercise capacities. PATIENTS AND METHODS A total of 44 patients with stable chronic heart failure underwent 5 weeks of exercise training, with electrical myostimulation or conventional aerobic training programmes. At baseline and after the training period, patients performed a symptom-limited cardiopulmonary exercise test and a 6-min walk test. RESULTS Oxygen uptake at the end of exercise (V.O2 peak) and at ventilatory threshold (V.O2 VT) increased after electrical myostimulation (p< 0.001) and conventional aerobic training (p< 0.001) training programmes. The slope of the relationship between V.O2 and workload was reduced after electrical myostimulation (p< 0.05), but not after conventional aerobic training. Recovery was improved after both training programmes (p< 0.05), and the distance walked in 6 min was increased (p< 0.001). These improvements were not statistically different between electrical myostimulation and conventional aerobic training. Moreover, electrical myostimulation induced greater improvements in patients with low exercise capacity, whereas conventional aerobic training induced improved performance in patients with average exercise capacity. CONCLUSION Five weeks of electrical myostimulation and conventional aerobic training exercise training produced similar improvements in exercise capacity in patients with chronic heart failure. However, electrical myostimulation appears to be more effective in patients with low exercise capacity than in those with average exercise capacity.

Functional Electrical Stimulation: Cardiorespiratory Adaptations and Applications for Training in Paraplegia

Regular exercise can be broadly beneficial to health and quality of life in humans with spinal cord injury (SCI). However, exercises must meet certain criteria, such as the intensity and muscle mass involved, to induce significant benefits. SCI patients can have difficulty achieving these exercise requirements since the paralysed muscles cannot contribute to overall oxygen consumption. One solution is functional electrical stimulation (FES) and, more importantly, hybrid training that combines volitional arm and electrically controlled contractions of the lower limb muscles. However, it might be rather complicated for therapists to use FES because of the wide variety of protocols that can be employed, such as stimulation parameters or movements induced. Moreover, although the short-term physiological and psychological responses during different types of FES exercises have been extensively reported, there are fewer data regarding the long-term effects of FES. Therefore, the purpose of this brief review is to provide a critical appraisal and synthesis of the literature on the use of FES for exercise in paraplegic individuals. After a short introduction underlying the importance of exercise for SCI patients, the main applications and effects of FES are reviewed and discussed. Major findings reveal an increased physiological demand during FES hybrid exercises as compared with arms only exercises. In addition, when repeated within a training period, FES exercises showed beneficial effects on muscle characteristics, force output, exercise capacity, bone mineral density and cardiovascular parameters. In conclusion, there appears to be promising evidence of beneficial effects of FES training, and particularly FES hybrid training, for paraplegic individuals.

Effects of combined electromyostimulation and gymnastics training in prepubertal girls.

Deley, G, Cometti, C, Fatnassi, A, Paizis, C, and Babault, N. Effects of combined electromyostimulation and gymnastics training in prepubertal girls. J Strength Cond Res 25(2): 520-526, 2011-This study investigated the effects of a 6-week combined electromyostimulation (EMS) and gymnastic training program on muscle strength and vertical jump performance of prepubertal gymnasts. Sixteen young women gymnasts (age 12.4 ± 1.2 yrs) participated in this study, with 8 in the EMS group and the remaining 8 as controls. EMS was conducted on knee extensor muscles for 20 minutes 3 times a week during the first 3 weeks and once a week during the last 3 weeks. Gymnasts from both groups underwent similar gymnastics training 5-6 times a week. Isokinetic torque of the knee extensors was determined at different eccentric and concentric angular velocities ranging from −60 to +240° per second. Jumping ability was evaluated using squat jump (SJ), counter movement jump (CMJ), reactivity test, and 3 gymnastic-specific jumps. After the first 3 weeks of EMS, maximal voluntary torque was increased (+40.0 ± 10.0%, +35.3 ± 11.8%, and +50.6 ± 7.7% for −60, +60, and +240°s−1, respectively; p < 0.05), as well as SJ, reactivity test and specific jump performances (+20.9 ± 8.3%, +20.4 ± 26.2% and +14.9 ± 17.2% respectively; p < 0.05). Six weeks of EMS were necessary to improve the CMJ (+10.1 ± 10.0%, p < 0.05). Improvements in jump ability were still maintained 1 month after the end of the EMS training program. To conclude, these results first demonstrate that in prepubertal gymnasts, a 6-week EMS program, combined with the daily gymnastic training, induced significant increases both in knee extensor muscle strength and nonspecific and some specific jump performances.

Effects of electrical stimulation pattern on quadriceps isometric force and fatigue in individuals with spinal cord injury.

Variable frequency trains (VFT) or train combinations have been suggested as useful strategies to offset the rapid fatigue induced by constant frequency trains (CFT) during electrical stimulation. However, most studies have been of short duration with limited functional application in those with spinal cord injury (SCI). We therefore tested force and fatigue in response to VFT, CFT, and combined patterns in strength training‐like conditions (6‐s contractions).

Effects of electrical stimulation pattern on quadriceps force production and fatigue

Introduction: Mixed stimulation programs (MIX) that switch from constant frequency trains (CFT) to variable frequency trains have been proposed to offset the rapid fatigue induced by CFT during electrical stimulation. However, this has never been confirmed with long stimulation patterns, such as those used to evoke functional contractions. The purpose of this study was to test the hypothesis that MIX programs were less fatiguing than CFTs in strength training‐like conditions (6‐s contractions, 30‐min). Methods: Thirteen healthy subjects underwent 2 sessions corresponding to MIX and CFT programs. Measurements included maximal voluntary isometric torque and torque evoked by each contraction. Results: There were greater decreases of voluntary and evoked torque (P < 0.05) after CFT than MIX, and mean torque was 13 ± 1% higher during the MIX session (P < 0.05). Conclusions: These findings confirm that combining train types might be a useful strategy to offset rapid fatigue during electrical stimulation sessions with long‐duration contractions. Muscle Nerve 49: 760–763, 2014