Cardiovascular,motor, and sensory responses to vestibular stimulation in athletes of different specializations

It was shown that the mean value of the heart’s chronotropic response to vestibular stimulation at different positions of the head and the duration of the sensory response (a vestibular illusion of counter-rotation) in athletes were inversely related to the relative amount of angular accelerations in exercises performed by athletes of different specializations. The strengths of the systolic blood pressure response were the same in athletes of different specializations. The strength and frequency of hand movements increased during the rotational load, and the accuracy of the reproduction of a specified effort declined; however, these changes were also unrelated to sporting specialization. In nonathletes, these parameters were reduced, the accuracy of effort being much more decreased than in athletes.     

Changes in heart rate variability of athletes during a training camp.

Heart rate variability (HRV) reflects regulatory processes of the cardiovascular system and reveals fractal characteristics. In this paper we investigated standard HRV parameters and scaling characteristics in ten athletes before, during, and after a 2-week training camp to assess the effects of short-term overtraining on cardiovascular control. High-resolution ECGs were recorded over 30 min under resting conditions 1 week before the training camp, after 1 week of training in the camp, and after 3-4 days of recovery. Standard HRV analysis was performed according to Task Force recommendations. Scaling characteristics were assessed, applying detrended fluctuation analysis (DFA). Standard HRV analysis showed significant changes in meanNN and rmssd during the training camp. DFA revealed three distinct regions of scale-invariance and significant alterations during the training camp. In conclusion, HRV might be used to monitor the training state in athletes.     

Types of circulation in people with varying physical training]

In 125 young healthy males the cardiac output was estimated by means of tetrapolar rheoplethysmography. The marked differences were found in indices of central hemodynamics and specific peripheral resistance between the groups of sportsmen and non-sportsmen in spite of almost equal systemic arterial pressure in both groups. These differences are greatly due to the types of hemodynamics and in lesser degree--to the level of physical training and trend of sporting training.     

No Effects of Successful Bidirectional SMR Feedback Training on Objective and Subjective Sleep in Healthy Subjects

There is a growing interest in the application of psychophysiological signals in more applied settings. Unidirectional sensory motor rhythm-training (SMR) has demonstrated consistent effects on sleep. In this study the main aim was to analyze to what extent participants could gain voluntary control over sleep-related parameters and secondarily to assess possible influences of this training on sleep metrics. Bidirectional training of SMR as well as heart rate variability (HRV) was used to assess the feasibility of training these parameters as possible brain computer interfaces (BCI) signals, and assess effects normally associated with unidirectional SMR training such as the influence on objective and subjective sleep parameters. Participants (n?=?26) received between 11 and 21 training sessions during 7 weeks in which they received feedback on their personalized threshold for either SMR or HRV activity, for both up- and down regulation. During a pre- and post-test a sleep log was kept and participants used a wrist actigraph. Participants were asked to take an afternoon nap on the first day at the testing facility. During napping, sleep spindles were assessed as well as self-reported sleep measures of the nap. Although the training demonstrated successful learning to increase and decrease SMR and HRV activity, no effects were found of bidirectional training on sleep spindles, actigraphy, sleep diaries, and self-reported sleep quality. As such it is concluded that bidirectional SMR and HRV training can be safely used as a BCI and participants were able to improve their control over physiological signals with bidirectional training, whereas the application of bidirectional SMR and HRV training did not lead to significant changes of sleep quality in this healthy population.     

Morphological and biochemical changes in old rat muscles: effect of increased use

Male Wistar rats were strength and swim trained during a substantial period of old age to determine the influence of aging and activity on the histochemical and metabolic characteristics of a predominantly slow (soleus) and a predominantly fast (plantaris) skeletal muscle. Strength training counteracted the age-related atrophy of the fibers and the age-induced changes in fiber-type distribution of both muscles. Swim training, on the other hand, was without any effect on these parameters. The activity of both mitochondrial and cytoplasmic enzymes became lower with aging in the soleus muscle, whereas only the activity of the cytoplasmic enzymes became lower in the plantaris. Strength training reduced the aerobic capacity of both muscles, whereas swim training had the opposite effect. Aging induced a lower glycogen concentration of the lateral gastrocnemius muscle. This was avoided by swim training. The phosphocreatine and adenosine 5'-triphosphate concentrations were unchanged with aging but became higher with strength training. The activity pattern, therefore, seems to have a considerable influence on the age-related modification of the histochemical and metabolic characteristics of skeletal muscles of the rat. The effect, however, is related to the recruitment pattern of the fiber populations and the form of activity.     

Effect of six weeks of dura disc and mini-trampoline balance training on postural sway in athletes with functional ankle instability

Lateral ankle sprain (LAS) is one of the most common injuries incurred during sporting activities, and effective rehabilitation programs for this condition are challenging to develop. The purpose of this research was to compare the effect of 6 weeks of balance training on either a mini-trampoline or a dura disc on postural sway and to determine if the mini-trampoline or the dura disc is more effective in improving postural sway. Twenty subjects (11 men, 9 women) with a mean age of 25.4 +/- 4.2 years were randomly allocated into a control group, a dura disc training (DT) group, or a mini-trampoline (MT) group. Subjects completed 6 weeks of balance training. Postural sway was measured by subjects performing a single limb stance on a force plate. The disbursement of the center of pressure was obtained from the force plate in the medial-lateral and the anterior-posterior sway path and was subsequently used for pretest and posttest analysis. After the 6-week training intervention, there was a significant (p < 0.05) difference in postural sway between pre- and posttesting for both the MT (pretest = 56.8 +/- 20.5 mm, posttest = 33.3 +/- 8.5 mm) and DT (pretest = 41.3 +/- 2.6 mm, posttest = 27.2 +/- 4.8 mm) groups. There was no significant (p > 0.05) difference detected for improvements between the MT and DT groups. These results indicate that not only is the mini-trampoline an effective tool for improving balance after LAS, but it is equally as effective as the dura disc.     

Dynamics of changes in the cardiovascular response to submaximal exercise during low-intensity endurance training with particular reference to the systolic time intervals

Eighteen male volunteers (aged 20-23 years), not involved in any sporting activities, were submitted to 13 weeks of training consisting of 30 min exercise [at 50%-75% maximal oxygen intake (VO2max)] on a cycle ergometer, performed 3 times a week. Every 4 weeks cardiac function was evaluated by measuring the systolic time intervals at rest and during submaximal cycle exercise. Stroke volume (SV), heart rate (HR) and blood pressure (BP) responses to submaximal exercise, VO2max and anaerobic threshold (AT) were also determined. Significant increases in VO2max, increases in AT and SV at the submaximal exercise intensities, as well as decreases in HR and BP were found after 4 weeks of training. Resting systolic time intervals were not affected by training, but during the submaximal cycle exercise the values of the pre-ejection period (PEP) and isovolumic contraction time (ICT) corresponding to HR of 100 beats.min-1 were significantly lowered after 13 weeks of training, whereas PEP, ICT and total electromechanical systole corresponding to HR of 130 beats.min-1 were significantly shortened by the 4th week. The ratios of PEP:LVET (left ventricular ejection time) and ICT:LVET during submaximal exercise were significantly lowered by training starting from the 8th week. These changes might be interpreted as evidence of the training-induced enhancement of the "contractility reserve", i.e. the ability to increase heart muscle contractility with increasing exercise intensity.     

A comparison of anthropometric and training characteristics among recreational male ironman triathletes and ultra-endurance cyclists

"The physique of Ironman triathletes was considered to be similar to that of cyclists. We intended to investigate differences and similarities in anthropometry and training between 83 Ironman triathletes competing in a qualifier for 'Ironman Hawaii' and 84 ultra-endurance cyclists competing in a qualifier for the 'Race across America'. The anthropometric and training characteristics were compared between these two groups of athletes; associations of anthropometric and training characteristics with race time were investigated using bi- and multi-variate analysis. The Ironman triathletes had shorter legs, lower circumferences of upper arm, thigh and calf and a lower skeletal muscle mass compared to the ultra- cyclists. The Ironman triathletes invested more weekly training hours but fewer weekly cycling hours than the ultra-cyclists; the ultra-cyclists completed more cycling kilometres per week. In the multi- variate analysis, the skin-fold thicknesses at abdominal (P = 0.02) and iliacal site (P = 0.02) as well as percent body fat (P = 0.0008) were associated with race time for the Ironman triathletes. The abdominal (P = 0.003) and the iliacal (P = 0.02) skin-fold thicknesses, percent body fat (P = 0.001) and cycling speed during training (P = 0.01) were related to cycling split time in the Ironman race. For the ultra-cyclists, percent body fat (P = 0.04) was related to race time. We concluded that anthropometry and training of Ironman triathletes were different when compared to ultra-endurance cyclists."     

Modeling human performance in running

This paper focuses on the characteristics of a model interpreting the effect of training on athletic performance. The model theory is presented both mathematically and graphically. In the model, a systematically quantified impulse of training produces dual responses: fitness and fatigue. In the absence of training, both decay exponentially with time. With repetitive training, these responses satisfy individual recurrence equations. Fitness and fatigue are combined in a simple linear difference equation to predict performance levels appropriate to the intensity of training being undertaken. Significant observed correlation of model-predicted performance with a measure of actual performance during both training and tapering provides validation of the model for athletes and nonathletes alike. This enables specific model parameters to be estimated and can be used to optimize future training regimens for any individual.     

Alterations of mechanical characteristics of human skeletal muscle during strength training

To investigate the influence of strength training on the mechanical characteristics of human skeletal muscle, 14 male subjects went through training of combined heavy concentric and eccentric contractions three times a week for 16 weeks. The strength training program consisted mainly of dynamic exercises for leg extensors with loads of 80 to 120% of one maximum repetition. The force-time curves produced during various vertical jumps were the basis for calculation of various mechanical parameters. In addition to a great increase (p less than 0.001) in maximal isometric force, heavy resistance strength training also caused significant (p less than 0.05-0.01) increases in heights and in various mechanical parameters in positive work phases of vertical and drop jumps. The increase in positive force during a fast dynamic contraction was correlated (p less than 0.01) with the reduced time to produce a certain submaximal force level in isometric condition. No changes in the elastic properties of the muscle were observed as judged from the difference between the counter-movement and squat jumps. When the training was followed by the 8-week detraining period a great decrease (p less than 0.001) in maximal force took place, but only minor changes (ns) were observed in fast force production.     

Finishers and nonfinishers in the 'Swiss Cycling Marathon ' to qualify for the 'Race Across America '

Knechtle, B, Knechtle, P, Rüst, CA, Rosemann, T, and Lepers, R. Finishers and nonfinishers in the 'Swiss Cycling Marathon' to qualify for the 'Race across America.' J Strength Cond Res 25(12): 3257-3263, 2011-We compared the characteristics of prerace anthropometry, previous experience, and training and support during the race in 39 finishers and 37 nonfinishers in the 'Swiss Cycling Marathon,' over 720 km. In this race, the cyclists intended to qualify for the 'Race across America,' the longest nonstop cycling race in the World from the West to the East of the USA. Finishers in the 'Swiss Cycling Marathon' had a lower body mass, a lower body mass index, lower circumferences of upper arm and thigh, a lower percent body fat, completed more weekly training units, covered more kilometers in the longest training ride, rode at a faster speed during training, rode more kilometers per week and for more hours, had more previous finishes in the 'Swiss Cycling Marathon' and a lighter race bike compared to the nonfinishers. In the bivariate analysis, the cycling distance per training unit (r = 0.37), the duration per training unit (r = 0.44), the speed per training unit (r = -0.59), using nutrition provided by the organizer (r = 0.50), and using own nutrition (r = 0.49) during the race were significantly and positively associated with race time. For practical applications, anthropometric characteristics such as a low body mass or low body fat were not related to race time, whereas training characteristics and nutrition during the race were associated with race time. The key to a successful finish in an ultraendurance cycling race such as the 'Swiss Cycling Marathon' seems a high speed in training and an appropriate nutrition during the race.     

Unabhängigkeit der bewertung zweier musterparameter von deren unterschiedlichkeitsgrad bei der Dressur

Bees were trained on a black disc (rewarded) against a smaller grey disc (unrewarded). Thus the bees had the choice of distinguishing between the two training figures by relying on the difference in size or on the difference in greyness or on both parameters. The aim of the present investigation was whether the relative weight of these parameters depended upon the differences in size and greyness presented during the training phase. 1. During the first two days of training the relative rating of these parameters changed in some, though not all individuals. In these cases the size of the discs rose in importance while the greyness was rated uniformly high (Fig. 3). Later, from the third day of training onwards the parameters were rated constantly. 2. Whenever size and greyness of the two training figures differed noticeably the bee relied on both parameters. The bee rated both parameters independently of the quantity of the differences in size and greyness presented during the training (Fig. 5). Thus the bee's analysis of the tested patterns cannot be attributed solely to the training paradigm, but seems to rely also on given (innate) “analyzers” (cf. Sutherland and Mackintosh, 1971). The type of training patterns only determines which “analyzers” influence the choice reaction. 3. The bee's “analyzer for size” had an influence on the choice reaction only if there was a noticeable size-difference between the training figures. The “analyzer for shades of grey”, however, strongly influenced the choice reactions also in those cases where the training figures showed no difference in greyness but only differences in size (Fig. 2).     

Physical training and plasma intermediate density lipoprotein cholesterol levels in men with hypertriglyceridemia

Plasma lipoprotein lipid levels including IDL cholesterol concentration, physical fitness parameters, and anthropometric data were measured in 10 men with primary hypertriglyceridemia during a 12 week program of moderate physical training. Reduced pulse rate at submaximal workload and increased work performed on the treadmill indicated that the men had increased their physical fitness during the training period. Body weight (-4.9%) and total skinfold thickness (-15.6%) fell during the training program. A characteristic fall (-23%) in plasma triglyceride levels was seen over the first 8 weeks training. Plasma IDL cholesterol concentration fell (-18%) after 2 weeks training but then rose after 8 weeks to levels which tended to be higher than baseline values. Our data suggest that regular physical exercise is more likely to raise levels of the "proatherogenic" IDL than to lower them in hypertriglyceridemic patients.     

Effects of sport (football) on growth: auxological, anthropometric and hormonal aspects

There are very few data available on the relationship between sporting activities, endocrine levels and changes in anthropometric measurements during growth. In order to study these relationships, we have made measurements of growth, changes in physical conformation and the plasma levels of several hormones [cortisol, dehydroepiandrosterone sulphate (DHEA-S), testosterone, growth hormone, somatomedin C, insulin, glycaemia and haemoglobin A1C] in 175 boys, aged 10-16 years, who have played football at a competitive level and in 224 boys, severing as controls, who have never performed sporting activities regularly. The football players were divided into prepubertal and pubertal subjects (10-11.99 years, 12-13.99 years and 14-16 years, chronological and bone age groups). Our results showed no significant differences in the growth indices between prepubertal athletes and controls, but the plasma level of DHEA-S was significantly higher (P less than 0.05) in the athletes. Pubertal football players, however, were significantly taller than the control subjects, particularly at 14-16 years chronological age. There were no such significant differences when bone age was considered. The pubertal football players were also more advanced in all biological indices of maturity, i.e. pubic hair, testicular volume and bone age. The increase in DHEA-S in pubertal football players, already seen in prepubertals, was also combined with a significant increase in testosterone, growth hormone and cortisol levels. Thus, in football players the DHEA-S level is already higher during prepuberty. This increase thus precedes all other indices of growth and maturation associated with puberty. We hypothesize that, while not excluding the possible influence of selection, as ours is a cross-sectional study, adrenal hyperactivity may be mainly responsible for the earlier onset of pubertal growth and maturity in exercising males.     

Effects of training frequency on the dynamics of performance response to a single training bout.

The aim of this study was to analyze the effect of an increase in training frequency on exercise-induced fatigue by using a systems model with parameters free to vary over time. Six previously untrained subjects undertook a 15-wk training experiment composed of 1) an 8-wk training period with three sessions per week (low-frequency training), 2) 1 wk without training, 3) a 4-wk training period with five sessions per week [high frequency training (HFT)], and 4) 2 wk without training. The systems input ascribed to training loads was computed from interval exercises and expressed in arbitrary units. The systems output ascribed to performance was evaluated three times each week using maximal power sustained over 5 min. The time-varying parameters of the model were estimated by fitting modeled performances to the measured ones using a recursive least squares method. The variations over time in the model parameters showed an increase in magnitude and duration of fatigue induced by a single training bout. The time needed to recover performance after a training session increased from 0.9 +/- 2.1 days at the end of low-frequency training to 3.6 +/- 2.0 days at the end of HFT. The maximal gain in performance for a given training load decreased during HFT. This study showed that shortening recovery time between training sessions progressively yielded a more persistent fatigue induced by each training.     

Training dogs with help of the shock collar: short and long term behavioural effects

Behavioural effects of the use of a shock collar during guard dog training of German shepherd dogs were studied. Direct reactions of 32 dogs to 107 shocks showed reactions (lowering of body posture, high pitched yelps, barks and squeals, avoidance, redirection aggression, tongue flicking) that suggest stress or fear and pain. Most of these immediate reactions lasted only a fraction of a second. The behaviour of 16 dogs that had received shocks in the recent past (S-dogs) was compared with the behaviour of 15 control dogs that had received similar training but never had received shocks (C-dogs) in order to investigate possible effects of a longer duration. Only training sessions were used in which no shocks were delivered and the behaviour of the dogs (position of body, tail and ears, and stress-, pain- and aggression-related behaviours) was recorded in a way that enabled comparison between the groups. During free walking on the training grounds S-dogs showed a lower ear posture and more stress-related behaviours than C-dogs. During obedience training and during manwork (i.e. excercises with a would-be criminal) the same differences were found. Even a comparison between the behaviour of C-dogs with that of S-dogs during free walking and obedience exercises in a park showed similar differences. Differences between the two groups of dogs existed in spite of the fact that C-dogs also were trained in a fairly harsh way. A comparison between the behaviour during free walking with that during obedience exercises and manwork, showed that during training more stress signals were shown and ear positions were lower. The conclusions, therefore are, that being trained is stressful, that receiving shocks is a painful experience to dogs, and that the S-dogs evidently have learned that the presence of their owner (or his commands) announces reception of shocks, even outside of the normal training context. This suggests that the welfare of these shocked dogs is at stake, at least in the presence of their owner.     

The search for genotypes that underlie human performance phenotypes

For a species spread throughout the world, humans are remarkably invariant; yet there has always been more interest in the slight differences between individuals than in the great commonality. This is especially true in athletic endeavours, where nearly immeasurable differences in performance can separate the winner from the rest of the competitors. There is little doubt that performance is influenced by environment, as the effects of diet and training on athletic ability have long been known, if not completely understood; however, the contribution of an individual's genetic make-up is less clear. The dominance of particular nationalities, ethnic groups, or families in various sporting events is often perceived as evidence that heritage (biological or cultural), plays a role in the development of athletic skills. Further complicating the issue are the interactions between genetic background and environment, as both of these fundamental arbiters of development rarely act independently. Despite the complexity of the problem, numerous researchers have attempted to elucidate the effects of genetic background on physical performance and, more recently, to identify the specific genetic variants that contribute to performance. This article reviews some of these studies with a focus on the methodologies employed.     

Influence of training in the dark or light phase on physiologic and metabolic parameters of Wistar rats submitted to aerobic exercise

Light and dark phase training may influences rodents’ physiologic parameters because these animals have nocturnal habits. Thus, we verify the effects of the training in different photoperiods on metabolism and corporal composition of rats. Eighteen rats were divided into three groups – G1: non-trained; G2: trained in the light phase; G3: trained in the dark phase. Rats were allowed to swim for 60 min, five times per week during six weeks. Trained animals presented a smaller weight gain and fat percentage in carcass. Rats of G3 increased gastrocnemius relative weight. The adipocyte diameter of G3 rats was smaller than the other groups. The levels of the total cholesterol, low-density proteins, and triacylglycerols were decreased in animals of G2 while the glycemia was increased. Training in light phase provided more alterations in the blood biochemical profile while the training in the dark increased the gastrocnemius weight and decreased the diameter of the adipocyte.     

Vibration training: an overview of the area, training consequences, and future considerations

The effects of vibration on the human body have been documented for many years. Recently, the use of vibration for improving the training regimes of athletes has been investigated. Vibration has been used during strength-training movements such as elbow flexion, and vibration has also been applied to the entire body by having subjects stand on vibration platforms. Exposure to whole-body vibration has also resulted in a significant improvement in power output in the postvibratory period and has been demonstrated to induce significant changes in the resting hormonal profiles of men. In addition to the potential training effects of vibration, the improvement in power output that is observed in the postvibratory period may also lead to better warm-up protocols for athletes competing in sporting events that require high amounts of power output. These observations provide the possibility of new and improved methods of augmenting the training and performance of athletes through the use vibration training. Despite the potential benefits of vibration training, there is substantial evidence regarding the negative effects of vibration on the human body. In conclusion, the potential of vibration treatment to enhance the training regimes of athletes appears quite promising. It is essential though that a thorough understanding of the implications of this type of treatment be acquired prior to its use in athletic situations. Future research should be done with the aim of understanding the biological effects of vibration on muscle performance and also the effects of different vibration protocols on muscle performance.     

1-Set vs. 3-set resistance training: a crossover study

This crossover study was conducted to investigate the effects of a 1-set and 3-set strength training program. The subjects were untrained men and women who were randomly signed into 1 of 3 groups: 10 subjects trained during the first 9 weeks (training period 1) with 1 set and 8-12 repetitions per set. After the break (9 weeks), they trained with 3 sets and 8-12 repetitions in training period 2. Twelve subjects started with the 3-set program and continued with the 1-set regime after the break. The control group (n = 7) did not train. The subjects were tested on 1 repetition maximum (1RM) for the biceps curl, leg press (unilateral: left and right), and bench press. Analysis of the data was done in a sampled manner for each strength training program (1-set and 3-set). The 1-set (n = 22) and 3-set (n = 22) programs led to significantly (p < 0.05) improved 1RM performances in every exercise. The relative improvements (%) for the 1RM were significantly higher during the 3-set program for the biceps curl and the bench press compared with the 1-set program. The control group exhibited no changes in any of the tested parameters over the course of this study. The design of this study allowed insight into the effects of different strength training volume without any genetical variations. The same subjects improved their 1RM during the 3-set program by 2.3 kg (biceps curl; corresponding effect size = 0.24), 8.9 kg (leg press right; 0.30), 10.9 kg (leg press left; 0.28), and 2.5 kg (bench press; 0.09) more than during the 1-set program. Depending on the goals of each trainee, these differences between the effects of different strength training volumes indicate that it may be worth spending more time on working out with a 3-set strength training regime.