One- or Two-Legged Standing

To highlight the capacity of one- and two-legged standing protocols when assessing postural behavior induced by a rigid ankle orthosis, 14 healthy individuals stood upright barefoot and wore either an elastic stocking on the preferred leg or a rigid orthosis with or without additional taping in one- or two-legged (TL) conditions. Traditional center-of-pressure (CP) measures were evaluated for the total two-feet resultant CP and under the feet (plantar CP). Focusing on the plantar CP displacements under the leg fitted with the various orthoses demonstrated particular postural behaviors for traditional parameters with main effects along the mediolateral axis. Only the TL protocol showed the limiting effects of the rigid shells on the inversion-eversion movements in healthy individuals.     

Analysis of Gymnastics Judges' Visual Search

Abstract

This study was designed to investigate the visual search patterns of gymnastics judges. The subjects were four national judges (experienced) and three local judges (novice). Three dependent variables were measured: the number and the location of ocular fixations during the evaluation of a gymnast's performance, and the number of errors made by the judges. Ocular fixations were studied by the corneal reflection technique with a NAC Eye-Movement Recorder. There was no statistical difference in the number of fixations for both groups of judges. However, the expert judges had 27% less fixations than the novice judges. A statistical difference was found between expert judges and novice judges for the location of fixations; experts had more fixations on the upper part of the gymnast's body, while novices concentrated their attention on the legs. The type of routine significantly affected the number of fixations; more fixations were found for optional routines. There was no statistical difference in the number of judgment errors made by the two groups of judges. However, novice judges detected only half the gymnast's errors detected by the expert judges.     

Effects of regular training at the same time of day on diurnal fluctuations in muscular performance

The aim of this study was to determine whether there is an effect of time of day on the adaptation to strength training at maximal effort. Fourteen participants took part in this experiment. Their peak anaerobic power (Wingate anaerobic test) and peak knee extension torque at six angular velocities (1.05, 2.10, 3.14, 4.19, 5.24 and 6.29 rad · s -1 ) were recorded in the morning (between 07:00 and 08:00 h) and in the evening (between 17:00 and 18:00 h) just before and 2 weeks after a 6 week course of regular training. Seven of them trained only in the morning and seven only in the evening. Multivariate analysis of variance revealed a significant group 2 pre-/post-training 2 time of day interaction effect for peak torque and peak anaerobic power. Before training, in both groups, peak torque and peak anaerobic power were significantly higher in the evening than in the morning. After training, there was no significant difference in peak torque and peak anaerobic power between the morning and the evening for the morning training group. In contrast, in the evening training group, peak torque and peak anaerobic power were higher in the evening than in the morning. As a result of training, both peak torque and peak anaerobic power increased from their initial values as expected. The morning training group improved their peak anaerobic power significantly in the morning and in the evening, the absolute increase being larger in the morning than in the evening. The evening training group did not improve their peak anaerobic power in the morning, whereas it improved significantly in the evening. Although peak torque was significantly improved by training in the morning and evening in both groups, the absolute increase was greater in the morning than in the evening in the morning training group, whereas the opposite was the case for the evening training group. These results suggest that training twice a week at a specific hour increases the peak torque and the peak anaerobic power specifically at this hour and demonstrates that there is a temporal specificity to strength training.     

Stretching and deep and superficial massage do not influence blood lactate levels after heavy-intensity cycle exercise

Abstract

The study aimed to assess the role of deep and superficial massage and passive stretching recovery on blood lactate concentration ([La^?]) kinetics after a fatiguing exercise compared to active and passive recovery. Nine participants (age 23 ± 1 years; stature 1.76 ± 0.02 m; body mass 74 ± 4 kg) performed on five occasions an 8-min fatiguing exercise at 90% of maximum oxygen uptake, followed by five different 10-min interventions in random order: passive and active recovery, deep and superficial massage and stretching. Interventions were followed by 1 hour of recovery. Throughout each session, maximum voluntary contraction (MVC) of the knee extensor muscles, [La^?], cardiorespiratory and metabolic variables were determined. Electromyographic signal (EMG) from the quadriceps muscles was also recorded. At the end of the fatiguing exercise, [La^?], MVC, EMG amplitude, and metabolic and cardiorespiratory parameters were similar among conditions. During intervention administration, [La^?] was lower and metabolic and cardiorespiratory parameters were higher in active recovery compared to the other modalities (P < 0.05). Stretching and deep and superficial massage did not alter [La^?] kinetics compared to passive recovery. These findings indicate that the pressure exerted during massage administration and stretching manoeuvres did not play a significant role on post-exercise blood La^? levels.     

Modelling training response in elite female gymnasts and optimal strategies of overload training and taper

Abstract

The aim of the study is the modelling of training responses with a variable dose-response model in a sport discipline that requires highly complex coordination. We propose a method to optimise the training programme plan using the potential maximal performance gain associated with overload and tapering periods. Data from five female elite gymnasts were collected over a 3-month training period. The relationship between training amounts and performance was then assessed with a non-linear model. The optimal magnitude of training load reduction and its duration were investigated with and without an overload period using simulation procedures based on individual responses to training. The correlation between actual and modelled performances was significant (R ² = 0.81 ± 0.02, P < 0.01). The standard error was 2.7%. Simulations revealed that taper preceded by an overload period allows a higher performance to be achieved compared to an absence of overload period (106.3 ± 0.3% vs. 105.1 ± 0.3%). With respect to the pre-taper load, the model predicts that optimal load reductions during taper were 48.4 ± 0.7% and 42.5 ± 1.0% for overloading and non-overloading strategies, respectively. Moreover, optimal durations of the taper period were 34 ± 0.5 days and 22 ± 0.5 days for overloading and non-overloading strategies, respectively. In conclusion, the study showed that the variable dose-response model describes precisely the training response in gymnasts.     

Book Review

Abstract

The mechanical responses (i.e. external contact forces and external power) of 25 elite rowers to a race-pace rowing protocol were investigated on the traditional fixed stretcher mechanism and the more recently introduced free-floating stretcher mechanism rowing ergometers. Using a Rowperfect rowing ergometer for both conditions, external contact forces at the handle, stretcher and sliding seat, as well as the displacements of the handle and stretcher, were recorded. The external power was calculated as the product of the force and velocity data from both the handle and stretcher. Significant differences (P < 0.05) between the two conditions for each mechanical parameter were observed. The fixed condition showed larger maximum values for forces and external power and average power throughout the rowing cycle. Moreover, rowing with the fixed mechanism generated higher inertial forces during the transition between the propulsion and recovery phases, especially at the catch of the cycle. The results suggest that: (i) muscular coordination may differ according to the stretcher mechanism used, which could have an impact on the physiological adaptations of muscles; and (ii) the free-floating mechanism may induce lower catch and maximum values for net joint forces and net joint moments that could decrease the risk of injury.     

Acute passive stretching in a previously fatigued muscle: Electrical and mechanical response during tetanic stimulation

Abstract

The aim of this study was to assess the effects of acute passive stretching on the electrical and mechanical response of a previously fatigued muscle. Eleven participants underwent maximal tetanic stimulations (50 Hz) of the medial gastrocnemius, before and after a fatiguing protocol and after a bout of passive stretching of the fatigued muscle. During contraction, surface electromyography (EMG), mechanomyography (MMG), and force were recorded. The following parameters were calculated: (1) the EMG root mean square (RMS), mean frequency, and fibre conduction velocity; (2) MMG peak-to-peak and RMS; (3) the peak force, contraction time, half-relaxation time, peak rate of force development (dF/dt) and its acceleration (d² F/dt ²). Fatigue reduced peak force by 18% (P < 0.05) and affected the other force, EMG, and MMG parameters. After stretching: (1) all EMG parameters recovered to pre-fatigue values; (2) MMG peak-to-peak remained depressed, while RMS recovered to pre-fatigue values; (3) the peak force, peak rate of force development and its acceleration were further reduced by 22, 18, and 51%, respectively, and half-relaxation time by 40% (P < 0.05). In conclusion, acute passive stretching, when applied to a previously fatigued muscle, further depresses the maximum force-generating capacity. Although stretching does not alter the electrical parameters of the fatigued muscle, it does affect the mechanical behaviour of the muscle–tendon unit.     

Effects of external loading on power output in a squat jump on a force platform: A comparison between strength and power athletes and sedentary individuals

The aim of this study was to determine the effects of external loading on power output during a squat jump on a force platform in athletes specializing in strength and power events (6 elite weight-lifters and 16 volleyball players) and in 20 sedentary individuals. Instantaneous power was computed from time-force curves during vertical jumps with and without an external load (0, 5 or 10 kg worn in a special vest). The jumps were performed from a squat position, without lower limb counter-movement or an arm swing. Peak instantaneous power corresponded to the highest value of instantaneous power during jumping. Average power throughout the push phase of the jump was also calculated. A two‐way analysis of variance showed significant interactions between the load and group effects for peak instantaneous power ( P < 0.01) and average power ( P < 0.001). Peak instantaneous power decreased significantly in sedentary individuals when moderate external loads were added. The peak instantaneous power at 0 kg was greater than that at 5 and 10 kg in the sedentary individuals. In contrast, peak instantaneous power was independent of load in the strength and power athletes. Mean power at 0 kg was significantly lower than at 5 kg in the athletes; at 0 kg it was significantly higher than at 10 kg in the sedentary males and at 5 and 10 kg in the sedentary females. In all groups, the force corresponding to peak instantaneous power increased and the velocity corresponding to peak instantaneous power decreased with external loading. The present results suggest that the effects of external loading on peak instantaneous power are not significant in strength and power athletes provided that the loads do not prevent peak velocity from being higher than the velocity that is optimal for maximal power output.     

The W(h)ine Club: women finding joy in academic work

The W(h)ine Club is a multidisciplinary women's research team which has been working together for the past 10 years. The idea for this Viewpoint piece grew as we participated in a Women in Research programme. The aim of the programme was to improve academic publications among women. A group of us in the programme found ourselves repeatedly referring to a time when we had worked together in a research project and the absolute joy we had experienced working together. We decided to write this reflection as the story of the W(h)ine Club, a space in which we complained, drank lots of wine, laughed and researched. All at the same time! What we realised was that women academics working together was a wonderful way to do research. Sharing our joys and sadness was often the glue that kept the team together and we learnt about research without realising it. In this Viewpoint we show that learning to research can be fun and that the bonds built in this process are powerful and validating.     

An Educational Case Study in Protocol Verification and Distributed Observation

This paper describes a case study presented to students in computer science during a course on formal techniques for protocol validation. The course teaches some basic notions on specification, simulation, verification, testing and distributed observation. The case study is the classical alternating-bit protocol. The exercise first consists of some simple modeling and simulation of the specification and verification of some basic service properties. It is then followed with the problem of observation of distributed executions of the protocol. This kind of experiment was found to be useful for students, since they gain an understanding of the importance and necessity of formal methods for protocol validation.