Differential reflex adaptations following sensorimotor and strength training in young elite athletes.

In young elite athletes the influence of a sensorimotor training (SMT = balance training) on strength, jump height and spinal reflex excitability was compared with adaptations induced by strength training (ST). Seventeen athletes were randomly assigned to either a SMT or a ST group. Before and after 6 weeks of training, maximal isometric strength (MVC) and rate of force development (RFD (max)) were determined. Changes in jump height and EMG activity were assessed during squat- (SJ), countermovement- (CMJ) and drop-jump (DJ). To evaluate neural adaptations, H-reflex recruitment was recorded at rest and during dynamic activation of the plantarflexors following stance perturbation. MVC was enhanced after ST but not influenced by SMT. RFD (max) was not affected by any training. Both SMT and ST significantly improved jump performance in SJ, CMJ, and DJ. Maximum H-reflex to maximum M-wave ratios (H (max)/M (max)-ratios) at rest remained unchanged. During stance perturbation, H (max)/M (max)-ratios were significantly reduced following SMT whereas ST augmented H (max)/M (max)-ratios (p < 0.05). In contrast to other studies, no changes in RFD were found. This may be explained by methodological and/or training specific differences. However, both SMT and ST improved jump performance in well trained young athletes but induced opposing adaptations of the H (max)/M (max)-ratio when measured during dynamic contractions. These adaptations were task-specific as indicated by the unchanged reflexes at rest. Decreased spinal excitability following SMT was interpreted as the attempt to improve movement control, whereas augmented excitability following ST accounts for the effort to enhance motoneuron output. Functionally, our results emphasise that SMT is not only beneficial for prevention and rehabilitation but also improves athletic performance.

Combinatory effects of high-intensity-strength training and sensorimotor training on muscle strength.

It has been shown in classical strength training studies using high loads that improvements in rate of force development are mainly due to adaptations in the intramuscular coordination. Adaptations following sensorimotor training were also characterized by improvements in the rate of force development during maximum voluntary isometric contraction. The purpose of the present study was to investigate neuromuscular adaptations of combined sensorimotor and classical strength training. Eighteen subjects were randomly assigned to two groups. Group 1 (SMT-HST) had to perform a period of sensorimotor training at first and a high-intensity strength training afterwards. Group 2 (HST-SMT) performed the high intensity strength training at first and the sensorimotor training after. Maximum voluntary isometric contraction and neuromuscular activation were measured at three occasions: Before training, after the first, and after the second period. The results after the first period confirmed the positive effects of both training regimen on rate of force development (13 % [SMT-HST] and 27 % [HST-SMT], p < 0.05) and on maximum strength (9 % [HST-SMT] and 12 % [SMT-HST], p < 0.05) during maximum voluntary contraction. Improvements caused by sensorimotor training could only be achieved, when it was performed at first. It is supposed that classical strength training with high loads basically improves the mechanical efficiency of the effectors, whereas sensorimotor training alters the afferent input on the central nervous system. In combination, the sensorimotor training can have preconditioning effects on the strength training. A combination of both training methods can thus be recommended, if the sensorimotor training is performed at first.

The effects of a sensorimotor training and a strength training on postural stabilisation, maximum isometric contraction and jump performance.

Previous studies revealed that adaptations following sensorimotor training, performed to improve functional joint or postural stability, were characterized by improvements in the rate of force development during maximum voluntary isometric contraction. In classical strength training studies using intense loads it has been shown that improvements in rate of force development is mainly due to adaptations in the intramuscular coordination. The purpose of the present study was to compare possible neuromuscular adaptations in two training groups following either sensorimotor or classical strength training over a period of four weeks. Additionally a control group was investigated to contrast the adaptations seen after training. Postural stability, maximum voluntary isometric contraction and performance in squat-jump and in drop-jump were measured before and after training. The results confirmed the positive effects of both training regimen on rate of force development and on maximum strength during maximum voluntary contraction as well as on jump performance, while only the improvements after the strength training were significant. Strength training reduced iMEG, while it was enhanced after sensorimotor training in most testing situations. Strength training had positive effects also on concentric contractions like squat-jump. The sensorimotor training improved performance in reactive drop-jump by enhanced neuromuscular activity immediately after ground contact. It is concluded that classical strength training with high loads basically improves the mechanical efficiency of the efferent drive on the motoneurons, whereas sensorimotor training alters the afferent input on the central nervous system. Both adaptations yield to specific effects during force development.

[Efficacy of intravenous immunoglobulin in the treatment of Birdshot retinochoroiditis]. / Efficacité et tolérance des immunoglobulines intraveineuses dans le traitement de la rétinochoroïdopathie de type Birdshot.

AIM: To evaluate the efficacy of intravenous immunoglobulin (IVIg) in the treatment of Birdshot retinochoroiditis. PATIENTS AND METHODS: Eighteen patients were followed-up prospectively in a total number of 37 patients recorded. Inclusion criteria were birdshot retinochoroiditis (BRC) according to the criteria defined by Ryan et al., and a decrease in visual acuity (VA). Efficacy was assessed by measurements of visual acuity and a decrease in inflammation and macular edema on fluorescein angiograms. RESULTS: Sex ratio=1, mean age was 51 (range 29 to 72 years), HLA A29 was positive in 100% of the patients. VA at baseline was 0.6+/-2.4 (range 0.25 to 0.9). Angiography showed retinal vasculitis in 32 patients (86.48%) and cystoid macular edema in 16 patients (43.24%). IVIg was administered at a dosage of 0.4g/kg/d for 4 days then 0.6g/kg/d for 2 days every 4 weeks. Follow-up lasted a mean of 2.7+/-2.0 years (range, 4 months to 5.6 years). Visual acuity of 35 out of 66 eyes (53%) increased by 2.6+/-1.5 (range 1 to 5). In 19 eyes out of 66 (29%), VA remained stable and in 12 eyes out of 66 (18%), VA decreased by -1.8+/-0.8 (ranges-4 to -1). Inflammation on fluorescein angiography improved in 17 patients (81%) and cystoid macular edema decreased in 65% of the cases. Side effects were rare. Treatment was discontinued for side effects in only 3 patients. DISCUSSION: BRC is a chronique disease threatening vision. Treatments including systemic corticosteroids and cyclosporin A may result in severe long-term side effects. IVIg is well tolerated and may be therapeutic alternative for the treatment of BRC.

Intravenous immunoglobulin (IVIg) for the treatment of birdshot retinochoroidopathy.

Intravenous polyclonal immunoglobulin (IVIg) treatment has been successfully used in a number of autoimmune conditions. Birdshot retinochoroidopathy (BRC) is a bilateral autoimmune posterior uveitis which, in its progressive form, frequently requires immunosuppressive therapy. We report a clinical study aimed at determining the tolerance and efficiency of IVIg treatment in patients with active BRC. The study was conducted in an open manner. Eighteen patients were included. The initial visual acuity (VA) was < or =20/30 in 26 eyes, 20/25 in five eyes, and 20/20 in five eyes. IVIg was given as sole treatment at 1.6 g/kg every four weeks for six months, followed by injections of 1.2-1.6 g/kg at six to eight-week intervals. The mean follow-up was 39 months, ranging between 12 and 53 months. The results showed that the final VA of the 26 eyes with an initial VA of < or =20/30 was increased by two lines or more in 14 eyes (53.8%) and decreased in two (7.7%). Of the five eyes with an initial VA of 20/25, four had improved to 20/20 and one remained stable. Of the five eyes with an initial VA of 20/20, four remained stable and one deteriorated to 20/25. When present, macular edema was improved in half of the eyes on fluorescein angiography. Benign side effects were observed in 12 patients: moderate transient arterial hypertension (7), headache (6), eczematous lesions (6), and hyperthermia (4). The results suggest that IVIg may represent a safe alternative therapy for patients with BRC.

Indocyanine green angiography in birdshot chorioretinopathy.

OBJECTIVE: Birdshot chorioretinopathy (BC) is an ocular inflammatory disease involving both the retina and the choroid. The study goal was to evaluate indocyanine green angiographic features in BC to assess choroidal involvement. DESIGN: Retrospective, observational case series. PARTICIPANTS: Fifty-two patients with BC documented with at least 1 concomitant fluorescein and indocyanine green angiogram. INTERVENTION: Indocyanine green angiography (ICGA) was performed according to a standard protocol used for inflammatory disorders. MAIN OUTCOME MEASURE: Indocyanine green angiographic signs were correlated with fundus photographs, fluorescein angiography, degree of inflammatory activity, and stage of disease. RESULTS: In active disease, three main features were observed. The principal finding, found in 100% of patients, was the presence of hypofluorescent dark dots during the intermediate phase of angiography; their evolutionary pattern was twofold, becoming either isofluorescent or remaining hypofluorescent at the late phase of angiography. The other two signs were fuzzy, indistinct choroidal vessels and late-diffuse choroidal hyperfluorescence. In chronic longlasting disease, the characteristic finding was the presence of hypofluorescent dark dots that persisted in the late phase of disease and is theorized to correspond either to chorioretinal atrophy (irregular geographic pattern) or to persistent choroidal granulomas (round oval form). CONCLUSIONS: Consistent ICGA findings in 52 patients allowed the authors to establish a fairly precise ICGA semiology for BC. This procedure enabled the authors to assess choroidal involvement, and, in selected cases, it also was found to be of diagnostic help and useful to monitor therapeutic intervention.