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Background Subacromial space (SS) narrowing may result in unsafe contact of rotator cuff tendons and bursa with the acromion, possibly promoting rotator cuff pathologies and pain. We measured SS in asymptomatic subjects after three movements employed for shoulder muscles' training. Participants and main outcome measures Twenty-five males (age 24±5years; stature 175±8 cm; body mass 74±12 kg) underwent SS ultrasound evaluation while executing with (WL) and without (NL) 4-kg load: 90° shoulder abduction (SA) without humerus rotation (90° neutral ); 90° SA maximal humeral external rotation (90° er ); maximum SA (above 90°) during upright row (UR). For inter-operator reliability analysis, a subset of 12 subjects was assessed by two operators. Results Intra/inter-operator reliability coefficients were high (ICC>0.87; standard error of measurement range: 0.23–0.51 mm; minimum detectable change range: 0.61–1.79 mm). ANOVA revealed significant differences between loads (p = 0.003, η 2 = 0.37) and angles (p 2 = 0.72), and interaction (p = 0.004, η 2 = 0.45). Normalized SS values WL were higher at 90° er vs. 90° neutral and UR (p neutral and both 90° er (p = 0.002) and UR (p = 0.009). Conclusions When holding a 4-kg load, SS is larger at 90° er than at 90° neutral and UR shoulder abduction positions. In unloaded condition, SS at 90° neutral is reduced compared to 90° er and UR.

Low intensity resistance training with slow movement and tonic force generation has been shown to create blood flow restriction within muscles that may affect thermoregulation through the skin. We aimed to investigate the influence of two speeds of exercise execution on skin temperature dynamics using infrared thermography. Thirteen active males performed randomly two sessions of squat exercise (normal speed, 1s eccentric/1s concentric phase, 1s; slow speed, 5s eccentric/5s concentric phase, 5s), using ~50% of 1 maximal repetition. Thermal images of ST above muscles quadriceps were recorded at a rate of 0.05Hz before the exercise (to determine basal ST) and for 480s following the initiation of the exercise (to determine the nonsteady-state time course of ST). Results showed that ST changed more slowly during the 5s exercise (p=0.002), whereas the delta (with respect to basal) excursions were similar for the two exercises (p>0.05). In summary, our data provided a detailed nonsteady-state portrait of ST changes following squat exercises executed at two different speeds. These results lay the basis for further investigations entailing the joint use of infrared thermography and Doppler flowmetry to study the events taking place both at the skin and the muscle level during exercises executed at slow speed.

Background One of the mechanisms responsible for enhancing muscular hypertrophy is the high metabolic stress associated with a reduced muscular oxygenation occurring during exercise, which can be achieved by reducing the speed of movement. Studies have tested that lowered muscle oxygenation artificially induced by an inflatable cuff, could provoke changes in prefrontal cortex oxygenation, hence, to central fatigue. It was hypothesized that (1) exercising with a slow speed of movement would result in greater increase in cerebral and greater decrease in muscle oxygenation compared with exercises of faster speed and (2) the amount of oxygenation increase in the ipsilateral prefrontal cortex would be lower than the contralateral one. Methods An ISS Imagent frequency domain near infrared spectroscopy (NIRS) system was used to quantify oxygenation changes in the vastus lateralis muscle and prefrontal cortex (contra- and ipsilateral) during unilateral resistance exercises with different speeds of movement to voluntary fatigue. After one maximal repetition (1RM) test, eight subjects performed three sets of unilateral knee extensions (∼50% of 1RM), separated by 2 min rest periods, following the pace of 1 s, 3 s and 5 s for both concentric and eccentric phases, in a random order, during separate sessions. The amount of change for NIRS parameters for muscle (ΔHb: deoxyhemoglobin, ΔHbO: oxyhemoglobin, ΔHbT: total hemoglobin, ΔStO2: oxygen saturation) were quantified and compared between conditions and sets by two-way ANOVA RM. Differences in NIRS parameters between contra- and ipsilateral (lobe) prefrontal cortex and conditions were tested. Results Exercising with slow speed of movement was associated to larger muscle deoxygenation than normal speed of movement, as revealed by significant interaction (set × condition) for ΔHb (p = 0.01), and by significant main effects of condition for ΔHbO (p = 0.007) and ΔStO2 (p = 0.016). With regards to the prefrontal cortex, contralateral lobe showed larger oxygenation increase than the ipsilateral one for ΔHb, ΔHbO, ΔHbT, ΔStO2 in each set (main effect of lobe: p p Discussion These findings provided evidence that speed of movement influences the amount of muscle oxygenation. Since the lack of oxygen in muscle is associated to increased metabolic stress, manipulating the speed of movement may be useful in planning resistance-training programs. Moreover, consistent oxygenation increases in both right and left prefrontal lobes were found, suggesting a complementary interaction between the ipsi- and contralateral prefrontal cortex, which also seems related to fatigue.

This study assessed how accurately professional swimmers can interpret instructions to swim “slow,” “moderate,” and “fast.” 8 distance swimmers (6 males, 2 females; M age = 19 yr., SD = 3) and 8 sprint swimmers (7 males, 1 female; M age = 18yr., SD = 1) performed an all-out 50-m crawl stroke and three sets of 8 × 50-m crawl stroke trials interpreting the coach's instruction to swim at slow, moderate, and fast paces. No differences were detected between groups in absolute speed. Nevertheless, distance and sprint swimmers significantly differed in speed normalized to their own 50-m all-out speed (effect sizes = 6.72, 6.20, 1.35 for slow, moderate, and fast, respectively), stroke frequency (effect sizes = 0.81, 1.12, 1.54, respectively), and blood lactate concentration (effect sizes = 0.99, 2.56, 1.70, respectively).

In breaststroke, at each arm action corresponds one leg kick; therefore, compared to the other strokes (front crawl, backstroke and butterfly), the contribution of the lower limbs is more important. However, it can be observed that the same distance can be covered at similar velocities with different stroke length (SL) and, as a consequence, stroke rate (SR). Hence, it seems that breaststroke swimmers can use different styles to achieve their goals. Therefore, the assessment of upper and lower limbs strength becomes very important along with the style being used during breaststroke performance. Twenty-four male and twenty female national-level breaststroke swimmers were divided in two groups for each gender, according to their SR (low-SR and high-SR). They performed 100 m breaststroke all-out performance in a 50 m swimming pool. SR, SL and velocity (v) were measured. To assess upper and lower limbs strength, swimmers underwent dry-land chin-up and jump & reach tests. Dry-land tests did not correlate to v (p > 0.05). SL inversely correlated to chin-up and directly correlated to jump & reach (p < 0.01). Regardless to the gender, low-SR had lower chin-up results than high-SR (males 0.19 ± 0.03 vs. 0.24 ± 0.04 nr kg-1, p < 0.01; females 0.13 ± 0.02 vs. 0.15 ± 0.03 nr kg-1, p < 0.05) and jumped higher than high-SR (males 31.74 ± 0.50 vs. 25.11 ± 0.55 % height, p < 0.001; females 22.93 ± 0.33 vs. 20.54 ± 0.63 % height, p < 0.01) swimmers. Despite many factors are involved in determining swimming performance, upper and lower limbs strength seems to be linked to a different breaststroke style in our group of swimmers. © 2013 Springer-Verlag Italia.

Intense sports practice has effects on normal locomotion which may predispose athletes to certain injuries. The aim of the study was to evaluate weather playing rugby can change the distribution of forces on the surface of the foot plantar region and if these possible changes are caused by the high loading and the postural stances that this sport involves. The evaluation was performed using a baropodometer in static and dynamic conditions. We studied a group of 23 professional rugby players (scrums and three-quarters) who regularly trained 4-times per week. A control group consisted of 17 non-athletic healthy subjects. Baropodometric analysis revealed significantly higher rear-foot surface area and pressure for both feet in static conditions in rugby players compared to controls. In dynamic conditions, rugby players exerted a significantly higher ground pressure with respect to controls. Within the group of rugby players, scrums had significantly higher pressure than three-quarters, as well as a pressure increase in the lateral foot area. We conclude that rugby players tend to adopt an unbalanced posture posteriorly. The higher ground pressure together with the prevalent load on the lateral foot area may be associated with a difficult control of foot stability, possibly due to the higher body weight and to the increased tone and trophism of the triceps surae subsequent to the various athletic gestures that the game demands. In agreement with the literature, the variations of foot support observed in rugby players may be associated with adaptations induced by this sport, thus favoring an increased risk of bone, joint and muscle traumas and pathologies.

Injury in the lower limbs is extremely frequent in most sport activities, particularly when prolonged running and physical contact are prominent features. A major challenge is the differential diagnosis between muscle, joint and nerve lesions, although it should always be considered that combined lesions are quite frequent. In this part of the review, the most frequent nerve entrapment and traumatic lesions involving the peripheral nerves in the lower limb are discussed.

Sport–related strenuous physical activity and trauma are among the causes of peripheral nerves injuries, due in most cases to direct blow, compression or repeated traction or friction. Although in most cases the diagnosis is obvious, subtle peripheral nerve injuries can be difficult to recognize and, in most cases, require the support of appropriate instrumental evaluations. This review is divided into two parts devoted to the most common upper and lower limb peripheral nerves injuries, the anatomical reasons, the clinical presentation and the most helpful diagnostic tools.

Exercise performed at a competitive level could deeply modify the immune system and the cytokine response of athletes. In this report, we demonstrated that young elite female artistic gymnasts (n = 16; age: 9-15 years) showed an increase of interleukin 6 (IL-6) and tumour necrosis factor alpha (TNF-α) mRNA expression in blood mononuclear cells (PBMCs), in comparison to girls performing the same sport at a recreational level (n = 16; age: 10-15 years). The increase of IL-6 and TNF-α mRNAs appeared to be directly linked to the intensity and duration of the training. Moreover, in elite athletes engaged in artistic gymnastics or in synchronised swimming (n =34; age: 9-15 years), IL-6 gene expression appeared to be modulated by the levels of circulating oestrogens: pre-pubertal athletes (n = 20; age: 11 ± 1 years) revealed a higher increase in IL-6 than pubertal athletes (n = 14; age: 14 ± 1.6 years). In pre-pubertal athletes, body mass index (BMI) percentile was inversely correlated with the increase of both IL-6 and TNF-α. The consequence of these events was the shift of the cytokine profile towards a pro-inflammatory status. These modifications, induced by training performed at an elite level, might negatively affect the growth of female children athletes.

In this study, the neck and head relative to the ground were more flexed, while the head relative to the neck was more extended, in the subjects who were blind than in the sighted subjects. The introduction of external (sound) or proprioceptive (mandibular position, look ahead) inputs modified craniocervical posture and relationships (extension) in both groups.

A new television technique that proved to be faster than conventional photographic analysis has been developed and applied to the evaluation of the head and body natural standing posture in 303 healthy children, ages 6 to 11, and in 186 healthy young adults. In the lateral plane all subjects had extended head (soft tissue Frankfurt plane), with parallel Camper's and occlusal planes. The neck was halfway between the horizontal and vertical planes. Most angles significantly correlated with each other. The occlusal and neck angles showed a significant effect of age, being larger in children than in adults. In children the neck was more flexed, and the occlusal plane was more inclined downward. The results were in accord with previous photographic evaluations showing that the applied method was reliable and could be usefully employed in postural investigations. The results also confirmed that in healthy subjects, regardless of age, the soft tissue Frankfurt plane is extended, not horizontal.