Neural influences on sprint running - Training adaptations and acute responses

Performance in sprint exercise is determined by the ability to accelerate, the magnitude of maximal velocity and the ability to maintain velocity against the onset of fatigue. These factors are strongly influenced by metabolic and anthropometric components. Improved temporal sequencing of muscle activation and/or improved fast twitch fibre recruitment may contribute to superior sprint performance. Speed of impulse transmission along the motor axon may also have implications on sprint performance. Nerve conduction velocity (NCV) has been shown to increase in response to a period of sprint training. However, it is difficult to determine if increased NCV is likely to contribute to improved sprint performance. An increase in motoneuron excitability, as measured by the Hoffman reflex (H-reflex), has been reported to produce a more powerful muscular contraction, hence maximising motoneuron excitability would be expected to benefit sprint performance. Motoneuron excitability can be raised acutely by an appropriate stimulus with obvious implications for sprint performance. However, at rest reflex has been reported to be lower in athletes trained for explosive events compared with endurance-trained athletes. This may be caused by the relatively high, fast twitch fibre percentage and the consequent high activation thresholds of such motor units in power-trained populations. In contrast, stretch reflexes appear to be enhanced in sprint athletes possibly because of increased muscle spindle sensitivity as a result of sprint training. With muscle in a contracted state, however, there is evidence to suggest greater reflex potentiation among both sprint and resistance-trained populations compared with controls. Again this may be indicative of the predominant types of motor units in these populations, but may also mean an enhanced reflex contribution to force production during running in sprint-trained athletes. Fatigue of neural origin both during and following sprint exercise has implications with respect to optimising training frequency and volume. Research suggests athletes are unable to maintain maximal firing frequencies for the full duration of, for example, a 100m sprint. Fatigue after a single training session may also have a neural manifestation with some athletes unable to voluntarily fully activate muscle or experiencing stretch reflex inhibition after heavy training. This may occur in conjunction with muscle damage. Research investigating the neural influences on sprint performance is limited. Further longitudinal research is necessary to improve our understanding of neural factors that contribute to training-induced improvements in sprint performance.

Effects of short-duration and long-duration exercise on lipoprotein(a)

Purpose: Most studies that use either a single exercise session, exercise training, or a cross-sectional design have failed to find a relationship between exercise and plasma lipoprotein(a) [Lp(a)] concentrations. However, a few studies investigating the effects of longer and/or more strenuous exercise have shown elevated Lp(a) concentrations, possibly as an acute-phase reactant to muscle damage. Based on the assumption that greater muscle damage would occur with exercise of longer duration, the purpose of the present study was to determine whether exercise of longer duration would increase Lp(a) concentration and creatine kinase. (CK) activity more than exercise of shorter duration. Methods: Ten endurance-trained men (mean +/- SD: age, 27 +/- 6 yr; maximal oxygen consumption [(V)over dotO(2max)], 57 +/- 7 mL(.)kg(-1) min(-1)) completed two separate exercise sessions at 70% (V)over dotO(2max). One session required 900 kcal of energy expenditure (60 +/- 6 min), and the other required 1500 kcal (112 +/- 12 min). Fasted blood samples were taken immediately before (0-pre), immediately after (0-post), 1 d after (1-post), and 2 d after (2-post) each exercise session. Results: CK activity increased after both exercise sessions (mean +/- SE; 800 kcal: 0-pre 55 +/- 11, 1-post 168 +/- 64 U(.)L(-1.)min(-1); 1500 kcal: 0-pre 51 +/- 5, 1-post 187 +/- 30, 2-post 123 +/- 19 U(.)L(-1.)min(-1); P < 0.05). However, median Lp(a) concentrations were not altered by either exercise session (800 kcal: 0-pre 5.0 mg(.)dL(-1), 0-post 3.2 mg(.)dL(-1), 1-post 4.0 mg(.)dL(-1), 2-post 3.4 mg(.)dL(-1); 1500 kcal: 0-pre 5.8 mg(.)dL(-1), 0-post 4.3 mg(.)dL(-1), 1-post 3.2 mg(.)dL(-1), 2-post 5.3 mg(.)dL(-1)). In addition, no relationship existed between exercise-induced changes in CK activity and Lp(a) concentration (800 kcal: r = -0.26; 1500 kcal: r = -0.02). Conclusion: These results suggest that plasma Lp(a) concentration will not increase in response to minor exercise-induced muscle damage in endurance-trained runners.

Do generalized visual training programmes for sport really work? An experimental investigation

We assessed the effectiveness of two generalized visual training programmes in enhancing visual and motor performance for racquet sports. Forty young participants were assigned equally to groups undertaking visual training using Revien and Gabor's Sports Vision programme (Group 1), visual training using Revien's Eyerobics (Group 2), a placebo condition involving reading (Group 3) and a control condition involving physical practice only (Group 4). Measures of basic visual function and of sport-specific motor performance were obtained from all participants before and immediately after a 4-week training period. Significant pre- to post-training differences were evident on some of the measures; however, these were not group-dependent. Contrary to the claims made by proponents of generalized visual training, we found no evidence that the visual training programmes led to improvements in either vision or motor performance above and beyond those resulting simply from test familiarity.

Helping the female partners of men abusing alcohol: a comparison of three treatments

Aim. To evaluate the effectiveness of three approaches to assisting the female partners of male problem drinkers with the stress imposed by the male's drinking. Design. Participants were assigned randomly via random number tables to one of three treatment conditions: supportive counselling, stress management or alcohol-focused couples therapy. Setting. The intervention took place at the Behaviour Research and Therapy Centre (BRTC), The University of Queensland. This research and training centre offers outpatient psychology services to the community. Participants. Sixty-one married women whose husbands drank heavily. Participants reported protracted alcohol problems, severe impact of alcohol on social functioning and severe marital distress. Measurement. The women's stress, alcohol consumption by the male, and relationship functioning were assessed at pre- and post-treatment and at 6-month follow-up. Interventions. All three treatments involved 15 1-hour sessions with the woman. In the alcohol-focused couple therapy, attempts were made to engage the man in these sessions. Results. Contrary to our predictions, there were few differences between the treatments. All three treatments were associated with reductions in the women's reported stress, with trends for somewhat greater reduction in the women's stress in the stress management and alcohol-focused couples therapy conditions than for supportive counselling. None of the treatments produced clinically significant reductions in men's drinking or relationship distress. Conclusion. The treatments ease stresses and burden but do not improve drinking or relationships. Limited power in the design restricted the capacity to detect differential treatment effects.

Using the World Wide Web to revolutionise technology transfer and training in the water and wastewater industries

Industry professionals of the near future will be supported by an IT infrastructure that enables them to complete a task by drawing on resources and people with expertise anywhere in the world, and access to knowledge through specific training programs that address the task requirements. The increasing uptake of new technologies enables information to reach a diverse population and to provide flexible learning environments 24 hours a day, 7 days a week. This paper examines one of the key areas where the World Wide Web will impact on the water and wastewater industries, namely technology transfer and training. The authors will present their experiences of developing online training courses for wastewater industry professionals over the last two years. The perspective is that of two people working at the coalface.

Effect of the movement speed of resistance training exercises on sprint and strength performance in concurrently training elite junior sprinters

The aim of this study was to determine the effects of 7 weeks of high- and low-velocity resistance training on strength and sprint running performance in nine male elite junior sprint runners (age 19.0 +/- 1.4 years, best 100 m times 10.89 +/- 0.21 s; mean +/- s). The athletes continued their sprint training throughout the study, but their resistance training programme was replaced by one in which the movement velocities of hip extension and flexion, knee extension and flexion and squat exercises varied according to the loads lifted (i.e. 30-50% and 70-90% of 1-RM in the high- and low-velocity training groups, respectively). There were no between-group differences in hip flexion or extension torque produced at 1.05, 4.74 or 8.42 rad . s(-1), 20 m acceleration or 20 m 'flying' running times, or 1-RM squat lift strength either before or after training. This was despite significant improvements in 20 m acceleration time (P < 0.01), squat strength (P< 0.05), isokinetic hip flexion torque at 4.74 rad . s(-1) and hip extension torque at 1.05 and 4.74 rad . s(-1) for the athletes as a whole over the training period. Although velocity-specific strength adaptations have been shown to occur rapidly in untrained and non-concurrently training individuals, the present results suggest a lack of velocity-specific performance changes in elite concurrently training sprint runners performing a combination of traditional and semi-specific resistance training exercises.

Can anticipatory skills be learned through implicit video-based perceptual training?

The aim of this experiment was to determine the effectiveness of two video-based perceptual training approaches designed to improve the anticipatory skills of junior tennis players. Players were assigned equally to an explicit learning group, an implicit learning group, a placebo group or a control group. A progressive temporal occlusion paradigm was used to examine, before and after training, the ability of the players to predict the direction of an opponent's service in an in-vivo on-court setting. The players responded either through hitting a return stroke or making a verbal prediction of stroke direction. Results revealed that the implicit learning group, whose training required them to predict serve speed direction while viewing temporally occluded video footage of the return-of-serve scenario, significantly improved their prediction accuracy after the training intervention. However, this training effect dissipated after a 32 day unfilled retention interval. The explicit learning group, who received instructions about the specific aspects of the pre-contact service kinematics that are informative with respect to service direction, did not demonstrate any significant performance improvements after the intervention. This, together with the absence of any significant improvements for the placebo and control groups, demonstrated that the improvement observed for the implicit learning group was not a consequence of either expectancy or familiarity effects.

Interval training program optimization in highly trained endurance cyclists

Purpose: The purpose of this study was to examine the influence of three different high-intensity interval training (HIT) regimens on endurance performance in highly trained endurance athletes. Methods: Before, and after 2 and 4 wk of training, 38 cyclists and triathletes (mean +/- SD; age = 25 +/- 6 yr; mass = 75 +/- 7 kg; (V)over dot O-2peak = 64.5 +/- 5.2 mL.kg(-1).min(-1)) performed: 1) a progressive cycle test to measure peak oxygen consumption ((V)over dotO(2peak)) and peak aerobic power output (PPO), 2) a time to exhaustion test (T-max) at their (V)over dotO(2peak) power output (P-max), as well as 3) a 40-kin time-trial (TT40). Subjects were matched and assigned to one of four training groups (G(1), N = 8, 8 X 60% T-max P-max, 1:2 work:recovery ratio; G(2), N = 9, 8 X 60% T-max at P-max, recovery at 65% HRmax; G(3), N = 10, 12 X 30 s at 175% PPO, 4.5-min recovery; G(CON), N = 11). In addition to G(1) G(2), and G(3) performing HIT twice per week, all athletes maintained their regular low-intensity training throughout the experimental period. Results: All HIT groups improved TT40 performance (+4.4 to +5.8%) and PPO (+3.0 to +6.2%) significantly more than G(CON) (-0.9 to + 1.1 %; P < 0.05). Furthermore, G(1) (+5.4%) and G(2) (+8.1%) improved their (V)over dot O-2peak significantly more than G(CON) (+ 1.0%; P < 0.05). Conclusion: The present study has shown that when HIT incorporates P-max as the interval intensity and 60% of T-max as the interval duration, already highly trained cyclists can significantly improve their 40-km time trial performance. Moreover, the present data confirm prior research, in that repeated supramaximal HIT can significantly improve 40-km time trial performance.

An evaluation of tobacco brief intervention training in three Indigenous health care settings in north Queensland

Objective: To evaluate the pilot phase of a tobacco brief intervention program in three Indigenous health care settings in rural and remote north Queensland. Methods: A combination of in-depth interviews with health staff and managers and focus groups with health staff and consumers. Results: The tobacco brief intervention initiative resulted in changes in clinical practice among health care workers in all three sites. Although health workers had reported routinely raising the issue of smoking in a variety of settings prior to the intervention, the training provided them with an additional opportunity to become more aware of new approaches to smoking cessation. Indigenous health workers in particular reported that their own attempts to give up smoking following the training had given them confidence and empathy in offering smoking cessation advice. However, the study found no evidence that anybody had actually given up smoking at six months following the intervention. Integration of brief intervention into routine clinical practice was constrained by organisational, interpersonal and other factors in the broader socio-environmental context. Conclusions/implications: While modest health gains may be possible through brief intervention, the potential effectiveness in Indigenous settings will be limited in the absence of broader strategies aimed at tackling community-identified health priorities such as alcohol misuse, violence, employment and education. Tobacco and other forms of lifestyle brief. intervention need to be part of multi-level health strategies. Training in tobacco brief intervention should address both the Indigenous context and the needs of Indigenous health care workers.

Knowledge of the national emergency telephone number and prevalence and characteristics of those trained in CPR in Queensland: baseline information for targeted training interventions

Members of the community contribute to survival from out-of-hospital cardiac arrest by contacting emergency medical services and performing cardiopulmonary resuscitation (CPR) prior to the arrival of an ambulance. In Australia there is a paucity of information of the extent that community members know the emergency telephone number and are trained in CPR. A survey of Queensland adults (n = 4490) was conducted to ascertain current knowledge and training levels and to target CPR training. Although most respondents (88.3%) could state the Australian emergency telephone number correctly, significant age differences were apparent (P < 0.001). One in five respondents aged 60 years and older could not state the emergency number correctly. While just over half the respondents (53.9%) had completed some form of CPR training, only 12.1% had recent training. Older people were more likely to have never had CPR training than young adults. Additional demographic and socio-economic differences were found between those never trained in CPR and those who were. The results emphasise the need to increase CPR training in those aged 40 and over, particularly females, and to increase the awareness of the emergency telephone number amongst older people. (C) 2002 Elsevier Science Ireland Ltd. All rights reserved.

Achieving effective supervision

Super vision probably does have benefits both for the maintenance and improvement of clinical skills and for job satisfaction, but the data are very thin and almost non-existent in the area of alcohol and other drugs services. Because of the potential complexity of objectives and roles in super vision, a structured agreement appears to be an important part of the effective supervision relationship. Because sessions can degenerate easily into unstructured socialization, agendas and session objectives may also be important. While a working alliance based on mutual respect and trust is an essential base for the supervision relationship, procedures for direct observation of clinical skills, demonstration of new procedures and skills practice with detailed feedback appear critical to super vision's impact on practice. To ensure effective super vision, there needs not only to be a minimum of personnel and resources, but also a compatibility with the values and procedures of management and staff, access to supervision training and consultation and sufficient incentives to ensure it continues.