Kim Nolte

Three dimensional musculoskeletal modelling of the abdominal crunch resistance training exercise

Abstract The aim of this study was to evaluate the benefits and limitations of using three dimensional (3D) musculoskeletal modelling (LifeModelerTM) in assessing the safety and efficacy of exercising on an abdominal crunch resistance training machine. Three anthropometric cases were studied, representing a 5th percentile female, and 50th percentile and 95th percentile male. Results indicated that the LifeModelerTM default model was capable of solving the forward dynamics simulations without adjustments. The modelling was able to indicate high risk for back injury when performing the abdominal crunch exercise as a result of the unacceptable intervertebral joint loading that occurs during the exercise. Individuals with small anthropometric dimensions such as some females and children cannot be accommodated suitably on the abdominal crunch machine which negatively impacts exercise posture and technique. Hip flexor muscle contribution in the execution of the exercise for the 5th percentile female was substantial thus reducing the efficacy of the exercise in isolating the abdominal muscles.

Three dimensional musculoskeletal modelling of the seated biceps curl resistance training exercise

The aim of this study was to evaluate the benefits and limitations of using three dimensional (3D) musculoskeletal modelling (LifeModeler™) in assessing the safety and efficacy of exercising on a seated biceps curl resistance training machine. Three anthropometric cases were studied, representing a 5th percentile female, 50th percentile and 95th percentile male. Results indicated that the LifeModeler™ default model was not adequate to solve the forward dynamics simulations. Therefore adjustments had to be made to the default model to successfully complete the forward dynamics simulations. The software was able to sufficiently highlight the shortcomings of the biceps curl machines engineered adjustability in relation to the anthropometric dimensions of the studied cases, as the 5th percentile female could not be accommodated suitably on the machine. High lumbar spine anterior/posterior shear forces for all anthropometric cases and maximum muscle tensions for the female and 50th percentile male indicate that the seated biceps curl exercise may pose risks for injuries. To conclude, it appears that 3D musculoskeletal modelling can be used to evaluate resistance training equipment such as the seated biceps curl machine. However the limitations as indicated by this study must be taken into consideration, especially when using the default LifeModeler™ model.

Doping in sport: Attitudes, beliefs and knowledge of competitive high school athletes in Gauteng Province

Objective. To determine the attitudes, beliefs and knowledge of talented young athletes residing in Gauteng regarding prohibited performance-enhancing drugs (PEDs) and anti-doping rules and regulations. Methods. This was a survey study using a quantitative research approach. South African TuksSport academy athletes at the High Performance Centre, University of Pretoria, and competitive high-school athletes at four private high schools in Gauteng completed the survey. A selfdetermined, structured questionnaire was used to establish the attitudes, beliefs and knowledge of the athletes. Results. A total of 346 (208 males, 138 females) athletes, mean (standard deviation) age 16.9 (1.4) years participated in the survey. According to this survey, 3.9% of the athletes in this survey admitted to using a prohibited PED and more than 14.0% of the athletes said they would consider using a prohibited PED if they knew they would not get caught. Ambition (46.0%) and emotional pressure (22.5%) were the primary reasons why the athletes would consider using prohibited PEDs. Even though coaches appeared to be one of the main sources of information (on PEDs and anti-doping rules), only 42.1% of the athletes felt that they were well informed. Conclusion. Controlling doping by means of testing is important. However, it may be necessary to put more emphasis on changing attitudes towards doping and implementing additional educational programmes.

Ad libitum vs. restricted fluid replacement on hydration and performance of military tasks.

INTRODUCTION The primary objective was to evaluate the effect of ad libitum vs. restricted fluid replacement protocol on hydration markers and performance in selected military tasks. The secondary objective was to determine if 300 ml x h(-1) could be considered a safe minimum fluid intake under the experimental conditions. METHODS Data were collected simulating a route march over 16 km. There were 57 subjects who participated in the study. RESULTS The mean pre-exercise body mass of the ad libitum group was 70.4 +/- 13.3 (SD) kg compared to 69.3 +/- 8.9 kg in the restricted group. The mean total fluid intake of the ad libitum group was 2.1 +/- 0.9 L compared to 1.2 +/- 0.0 L in the restricted group. The ad libitum and restricted intake groups, respectively, lost a mean of 1.05 kg +/- 0.77 (1.5%) and 1.34 kg +/- 0.37 (1.9%). Calculated sweat rate was 608 +/- 93 ml x h(-1) compared to 762 +/- 162 ml x h(-1) in the ad libitum group. DISCUSSION There were no significant differences for either urine specific gravity (USG) or urine osmolality (UOsm) before or after the exercise. It is not clear whether fluid intake and calculated sweat rates are causally related or explained by their codependence on a third variable; for example, the exercising metabolic rate. Thus, 300 ml x h(-1) intake could be considered a current safe minimum water intake for soldiers of similar mass under similar experimental conditions, namely similar exercise durations at equivalent exercise intensities in a moderate, dry climate.

Sports injuries in adults: overview of clinical examination and management

Abstract A wide variety of anatomical structures can be involved in a sports injury. To return to play as soon as possible is of utmost importance to an athlete, and in order to achieve this, a correct, all-inclusive diagnosis, a well-focused treatment plan, and a management plan that strives to offer protection are essential. This article aims to give an overview of acute and overuse (chronic) sports injuries in adults, the approach to an accurate diagnosis and the management strategies that are available. A literature review was conducted of scientific journals, text and internet material, including a Medline and PubMed search. Literature was selected for its in-depth data and well-researched information. Key search terms included “acute and overuse injuries”, as well as “sports injuries diagnosis and management” to address current and relevant scientific data on the examination and management of sports injuries in adults. The literature review indicated that sports injuries (both acute and overuse) are increasing in number due to the growing interest in physical activity and sport, as well as the enhanced intensity of training programmes. Adults are vulnerable to both types of sports injuries, and the age of occurrence of overuse injuries varies in competitive and non-competitive athletes. The importance of making an accurate diagnosis cannot be overemphasised. To assist the clinician in making an accurate diagnosis, a comprehensive history, physical examination and appropriate special investigations are mandatory. Familiarity with the demands of the athletes sport may also prove useful. The approach to the management of acute and overuse injuries differs, with the emphasis in acute injuries being on treating the effect (torn, broken, displaced) and in chronic injuries on treating the cause (intrinsic or extrinsic). There have been numerous advances in the management of sports injuries, however further research is still warranted in this area. Follow-up articles will focus more in-depth on specifics with regard to clinical examination, special investigations and management options.

Total body water, electrolyte, and thermoregulatory responses to ad libitum water replacement using two different water delivery systems during a 19-km route march

Abstract Nolte, HW, Nolte, K, and van der Meulen, J. Total body water, electrolyte, and thermoregulatory responses to ad libitum water replacement using two different water delivery systems during a 19-km route march. J Strength Cond Res 29(11S): S88–S93, 2015—Hands-free hydration systems are often advocated for improved hydration and performance in military populations. The aim was to assess whether such systems indeed result in improved hydration in exercising soldiers. Subjects were required to complete a route march while consuming water ad libitum from either a hydration bladder (BG) or traditional canteen (CG). Water intakes of 538 ml·h−1 (BG) and 533 ml·h−1 (CG) resulted in no differences for changes in body mass, serum [Na+], plasma osmolality, total body water, or time required to complete the march. There were no differences between peak exercise core temperature of the BG (38.9° C) and CG (38.7° C) groups. There were no differences between the groups for fluid balance, thermoregulation, or performance. This is a not a surprising finding because the amount of fluid consumed ad libitum is determined by changes in serum osmolality and not the fluid delivery system as often proposed.

The correlation between the health-related fitness of healthy participants measured at home as opposed to fitness measured by sport scientists in a laboratory

Background: Fitness is defined in the health context as a state of good health or physical condition, primarily as a result of exercise and proper nutrition. Conventional methods of measuring fitness are expensive, time consuming and require specialised methods. There is a need for noninvasive, fast methods of assessing health-related fitness and activity in athlete and non-athlete populations. The aim of this study was to establish any correlation between participants’ self-assessed health-related fitness (HRF) index and the HRF index determined by sports scientists, as well as the laboratory-assessed HRF index and maximum oxygen uptake (VO2max) determined by sports scientists via direct methods in a laboratory, and finally, to determine any potential correlation between an activity-recall questionnaire (Kasari) and VO2max. Method: The participants consisted of 169 male and female volunteers between the ages of 18 and 55 years, taking neither supplements nor medication. The University of Pretoria’s HRF index protocol was first carried out by participants on their own at home, and then in the laboratory under the supervision of sport scientists. The complete datasets of 150 participants were statistically analysed to establish correlations. Results: The results indicated highly significant and substantial correlations (ρ = 0.696, p < 0.001) between the participants’ self-assessed HRF index and measurements by the sports scientists. There were moderate correlations between the laboratory-assessed HRF index and the direct VO2max (ρ = 0.512, p < 0.005), as well as the indirect VO2max (ρ = 0.588; p < 0.001). A significant correlation was found between the self-assessed HRF index and the indirect VO2max (ρ = 0.454; p < 0.001). The Kasari questionnaire correlated only weakly with the indirect VO2max (ρ = 0.278, p < 0.002) and not at all with the direct VO2max (ρ = 0.072, p < 0.731). Conclusion: Indications are that this test protocol may be conducted at home by individuals, without supervision, to determine exercise ability or fitness, or to monitor changes in physical fitness, thereby limiting expenses and costs.

Three-dimensional musculoskeletal modelling of the seated row resistance-training exercise

Objective . To evaluate whether three-dimensional (3D) musculoskeletal modelling could be effective in assessing the safety and efficacy of exercising on a seated row resistance-training machine. The focus of the evaluation was on biomechanical and anthropometric considerations of the end user. Methods. Three anthropometric cases were created; these represented a 5th percentile female as well as a 50th and a 95th percentile male based on body mass index. Two repetitions, with a resistance equal to 50% of the functional strength of one repetition maximum (1RM) for each anthropometric case, were performed. Results. Results indicate that the default model of the LifeModeler software has important limitations that should be taken into consideration when used to evaluate exercise equipment. Adjustments had to be made to the model to solve the forward dynamics simulations; as a result, no muscle forces or contraction values were obtained. This negatively influenced the value of the results as these parameters are important when analysing an exercise. The seated row resistance-training machine’s engineered or manufactured adjustability was sufficient, as it appeared to accommodate the three anthropometric cases adequately during execution of this exercise. Conclusion. It appears that 3D musculoskeletal modelling can be used to evaluate resistance-training exercises such as the seated row; however, the limitations indicated by this study must be taken into consideration, especially when using the default LifeModeler model

Exercise prescription in the management of rheumatoid arthritis

Abstract Background: Over the last few years, the types of exercises prescribed for patients with rheumatoid arthritis (RA) have changed. There is also increasing knowledge on the physical status and physical activity levels of these patients. This article aims to give an overview of the physical status, physical activity levels and appropriate exercise prescription for patients with RA. Method: A literature search was conducted of scientific journals and text, including Medline and PubMed (1980–2012). Literature was selected for its in-depth data and well researched information. Key search terms included “RA and exercise therapy”, as well as “physical activity levels and physical status of patients with RA”. Results: The literature indicated that RA has a major impact on physical and psychological health. Over the past decade, there has been growing evidence of the health benefits of physical activity for patients with RA. Despite this evidence, patients with RA are less physically active than the general population. The types of exercises prescribed for patients with RA have changed from the traditionally prescribed isometric and range-of-motion exercises. However, proper choice and appropriate utilisation of exercise is essential in order to provide a therapeutic effect. Conclusion: Although pharmacological interventions have largely improved RA management, exercise therapy remains an important part of treatment. Despite the known benefits of physical activity and exercise, patients with RA are less physically active than the general population.