Action Observation Combined With Conventional Training Improves the Rugby Lineout Throwing Performance: A Pilot Study

Combining action observation (AO) and physical practice contributes to motor skill learning, and a number of studies pointed out the beneficial role of AO training in improving the motor performance and the athletes' movement kinematics. The aim of this study was to investigate if AO combined with immediate conventional training was able to improve motor performance and kinematic parameters of a complex motor skill such as the lineout throw, a gesture that represents a key aspect of rugby, that is unique to this sport. Twenty elite rugby players were divided into two groups. The AO group watched a 5-min video-clip of an expert model performing the lineout throw toward a target at 7 m distance and, immediately after the AO, this group executed the conventional training, consisting of six repetitions x five blocks of throws. The CONTROL group performed only the conventional lineout training. Intervention period lasted 4 weeks, 3 sessions/week. The AO group showed significant improvements in throwing accuracy (i.e., number of throws hitting the target), whilst no significant changes were observed in the CONTROL group. As concerns kinematic parameters, hooker's arm mean velocity significantly increased in both groups, but the increase was higher in AO group compared to CONTROL group. Ball velocity significantly increased only in the AO group, whereas ball angle release and ball spinning significantly decreased in both groups, with no differences between groups. Finally, no significant changes in knee and elbow angles were observed. Our results showed that the combination of AO and conventional training was more effective than a conventional training alone in improving the performance of elite rugby players, in executing a complex motor skill, such as the lineout. This combined training led to significant improvements in throwing accuracy and in hooker's and ball's kinematic parameters. Since AO can be easily implemented in combination with conventional training, the results of this study can encourage coaches in designing specific lineout training programs, which include AO cognitive training

Calpain-1 resident in lipid raft/caveolin-1 membrane microdomains plays a protective role in endothelial cells.

We are here reporting that calpain-1 is a constitutive component of a distinct lipid raft/caveolin-1 microdomain isolated from bEnd5 cells in association with endothelial nitric oxide synthase (eNOS) and heat shock protein 90 (HSP90). Perturbations in intracellular calcium concentration by Ca2+-ionophore A23187 or prolonged cell exposure to high glucose induce a significant decrease in the level of eNOS accompanied by a recruitment of additional HSP90 molecules at this site. In these conditions the cells are more resistant to cell death by Ca2+ overload. The decrease of eNOS has been due not only to its Ca2+-mediated release from the caveolin-1 aggregates but also to its digestion by calpain-1. The specific involvement of calpain-1 in digestion of eNOS is supported by the preventive effect of a synthetic calpain inhibitor (CI-2) and by the absence of calpain-2 and calpastatin in the caveolin-1 microdomain. These results suggest that the protein adjustments observed in lipid raft/caveolin-1 microdomains could be visualized as a process required to protect the cells against NO overproduction and aberrant calpain activation. Alterations in eNOS, calpain-1 and HSP90 levels have been observed in aorta of Zucker Diabetic Rats (ZDR). The loss of HSP90 occurring in these animals indicates an aberrant activation of calpain and thereby the transition from a physiological to a pathological cell condition

Age-related analysis of insulin resistance, body weight and arterial pressure in the Zucker fatty rat

The evolution with ageing of insulin resistance, body weight (BW) and mean arterial pressure (MAP) was studied in a group of Zucker fatty rats (ZFRs, n = 22), between 7 and 16 weeks of age, compared with an age-matched control group of Zucker lean rats (ZLRs, n = 22). The minimal model of glucose kinetics was applied to estimate glucose effectiveness, S(G), and insulin sensitivity, S(I), from insulinaemia and glycaemia measured during a 70 min intravenous glucose tolerance test. No correlation was found between S(G) and age in both ZFR and ZLR groups. No significant changes in mean S(G) between the two groups indicated no alteration of glucose-mediated glucose disposal. Estimates of S(I) from individual ZFRs were independent of age and, on average, showed 83% reduction (P < 0.001) compared with the ZLR group. Despite the lack of alteration of S(I) with age, the ZFR group showed an age-related increase of MAP, which correlated with increasing BW (r = 0.71 and P < 0.001). These results support the hypothesis that in our ZFRs, as a suitable genetic model of obesity and hypertension, insulin resistance is fully established at the age of 7 weeks and remains practically unaltered until at least the sixteenth week. An age-related increase in arterial pressure, observed in this strain, relates more properly to increasing BW, rather than insulin resistance. Development of hypertension with increasing age and BW may result from an enhanced insulin-mediated activity of the sympathetic nervous system, as observed in our previously reported study

Postural control after a strenuous treadmill exercise

The effect of a strenuous treadmill exercise on body stability and the mechanisms associated with it have been studied with two different experimental protocols. The former investigation was based on stabilometric and metabolic measurements performed in basal condition and after a strenuous treadmill exercise whilst the latter dealt with the study of the early postural response to a 3s-bilateral soleus muscle vibration after the strenuous exercise. Our exercise protocol was able to induce an important generalized metabolic fatigue, as assessed by the obtained peak values in the measured metabolic parameters, and resulting in a short-lasting body destabilization. A linear relationship between sway path and oxygen uptake was found. Thus, the short duration of body instability could be likely due to the quite rapid recovery of oxygen uptake. Further, the fatigue-induced body instability did not associate with changes in the early postural response to soleus muscle vibration. The present study cannot rule out the possibility that further central and/or peripheral mechanisms, influencing the postural control, may play a role in the fatigue-induced changes in body sway

IVGTT-based simple assessment of glucose tolerance in the Zucker fatty rat: Validation against minimal models

For the assessment of glucose tolerance from IVGTT data in Zucker rat, minimal model methodology is reliable but time- and money-consuming. This study aimed to validate for the first time in Zucker rat, simple surrogate indexes of insulin sensitivity and secretion against the glucose-minimal-model insulin sensitivity index (SI) and against first- (φ1) and second-phase (φ2) β-cell responsiveness indexes provided by C-peptide minimal model. Validation of the surrogate insulin sensitivity index (ISI) and of two sets of coupled insulinbased indexes for insulin secretion, differing from the cut-off point between phases (FPIR3- SPIR3, t = 3 min and FPIR5- SPIR5, t = 5 min), was carried out in a population of ten Zucker fatty rats (ZFR) and ten Zucker lean rats (ZLR). Considering the whole rat population (ZLR+ZFR), ISI showed a significant strong correlation with SI (Spearman's correlation coefficient, r = 0.88; P<0.001). Both FPIR3 and FPIR5 showed a significant (P<0.001) strong correlation with φ1 (r = 0.76 and r = 0.75, respectively). Both SPIR3 and SPIR5 showed a significant (P<0.001) strong correlation with φ2 (r = 0.85 and r = 0.83, respectively). ISI is able to detect (P<0.001) the well-recognized reduction in insulin sensitivity in ZFRs, compared to ZLRs. The insulin-based indexes of insulin secretion are able to detect in ZFRs (P<0.001) the compensatory increase of first- and second-phase secretion, associated to the insulinresistant state. The ability of the surrogate indexes in describing glucose tolerance in the ZFRs was confirmed by the Disposition Index analysis. The model-based validation performed in the present study supports the utilization of low-cost, insulin-based indexes for the assessment of glucose tolerance in Zucker rat, reliable animal model of human metabolic syndrome

Acute and Chronic Catabolic Responses to CrossFit® and Resistance Training in Young Males

Given the wide variety of conditioning program trainings employed, the present study compared the catabolic effects induced by CrossFit&reg; and resistance training in moderately trained subjects. Twenty males joined either the CrossFit&reg; group (n = 10; 30 min/day of &ldquo;workout of the day&rdquo;) or the resistance training (RT) group (n = 10; 30 min/day of resistance exercises) thrice a week, for 8 weeks. Salivary levels of cortisol, interleukin 1-beta (IL-1&beta;), and uric acid were assessed via enzyme-linked immunosorbent assays before (PRE) and 30-min after (POST) SESSION 1 and SESSION 24. Variables&rsquo; percentual changes were computed as (POST-PRE)/PRE*100 in each session (&Delta;%). CrossFit&reg; acutely increased cortisol levels in both sessions, with a significant decrease in &Delta;%cortisol from SESSION 1 to 24. In the RT group, cortisol values decreased in both sessions, only acutely. A significant decrease in IL-1&beta; levels was registered acutely in both groups, in both sessions, whereas &Delta;%IL-1&beta; was not different between the two groups. While uric acid levels increased in both groups acutely, a chronic downregulation of &Delta;%uric acid, from SESSION 1 to 24, was appreciated for the RT group only. Overall, CrossFit&reg; appeared to induce more intense effects than the RT program as to the investigated catabolic responses

Boosting and consolidating the proprioceptive cortical aftereffect by combining tendon vibration and repetitive TMS over primary motor cortex

Tendon vibration of a limb elicits illusory movements in the direction that the vibrated muscle would be stretched, followed by a transient perception of movement in the opposite direction, that was demonstrated to correspond to a \u201ccortical\u201d aftereffect (Goodwin et al. Science 175:1382\u20131384, 1972). Primary motor cortex (M1) excitability of the non-vibrated antagonist muscle of the vibrated muscle increased during vibration and decreased thereafter. The cortical aftereffect is of interest when considering the possibility to use tendon vibration in rehabilitation for restoring unbalance activity between antagonistic muscles but, due to its short-lasting duration, has not been explored so far. We investigated the possibility to consolidate the cortical aftereffect by combining tendon vibration with a concomitant high-frequency 5-Hz repetitive transcranial magnetic stimulation (rTMS) protocol. The distal tendon of the flexor carpi radialis muscle (FCR) was vibrated and concomitantly a 2-min 5-Hz rTMS protocol was administered on the left hemi-scalp hot spot of the vibrated FCR or its antagonist muscle (extensor carpi radialis (ECR)). We found that this protocol induced a pattern of unbalanced M1 excitability between vibrated muscle and its antagonist with increased excitability of the FCR and decreased excitability of ECR cortical areas, which persisted up to 30&nbsp;min

Model-based indexes in ZLR and ZFR groups.

<p>Model-based indexes in ZLR and ZFR groups.</p

Insulinaemia profiles for two ZLRs from control population.

<p>Vertical line represented the cut-off point between first- and second-phase secretion (3^rd min in panel A and 5^th min in panel B).</p