The Effect of Various Body Positions on Performance of the Isometric Mid-Thigh Pull

The purpose of this dissertation was to evaluate the effects of changing body position on the execution of the isometric mid-thigh pull (IMTP). Furthermore, while there is evidence to suggest that there is an effect of familiarization on performance of maximal strength tests, there has been no known research evaluating the effect of learning on the IMTP. The effect of familiarization was assessed by evaluating changes in variables obtained from the IMTP. Subjects did not statistically improve over the five IMTP testing sessions, regardless of the body position used, or if subjects had previous experience with weightlifting derivatives. This may indicate that little familiarization is needed for subjects to perform the IMTP before acute increases due to learning stabilize. When body positions were compared, there were differences in force production whether subjects had or did not have experience with weightlifting movements. The magnitude of difference between body position was affected by weightlifting movement experience; lifters with \u3e6 months experience with weightlifting had larger differences in force production between position. Average muscle activation for a variety of muscles, evaluated with surface EMG, appeared to differ between body positions, although these positions are idiosyncratic to experience level. In particular, lumbar erector spinae activation was higher in the bent position for both groups, which may have implications for low back injury risk.In entirety, it appears that if maximizing force production is the goal, the upright positon is optimal. Furthermore, the differing body positions have meaningfully different effects on how 3 much individual muscles are activated between positions. Lastly, substantial familiarization does not appear to be necessary before subjects perform the IMTP

Extravehicular activities limitations study. Volume 1: Physiological limitations to extravehicular activity in space

This report contains the results of a comprehensive literature search on physiological aspects of EVA. Specifically, the topics covered are: (1) Oxygen levels; (2) Optimum EVA work; (3) Food and Water; (4) Carbon dioxide levels; (5) Repetitive decompressions; (6) Thermal, and (7) Urine collection. The literature was assessed on each of these topics, followed by statements on conclusions and recommended future research needs

THE EFFECTS OF SPINAL MANIPULATIVE THERAPY ON ISOKINETIC STRENGTH AND POSTACTIVATION POTENTIATION

Spinal manipulative therapy (SMT) is a therapeutic procedure employed by various healthcare practitioners for alleviating acute and chronic musculoskeletal complaints. This form of treatment is also delivered to enhance the performance and augment the rehabilitation of athletes. However, despite research findings alleging the strength-modulating effects of SMT alongside numerous professional athletes’ positive anecdotal claims concerning its results, the physiological processes to explain its effects remain largely unexplained. Therefore, the purpose of this work was to investigate the effects of SMT in a college-aged sample population with two experiments. The first study examined the effect of SMT targeting the lumbosacral region on concentric force production of the knee extensors and flexors. A randomized, controlled, single-blind crossover design was utilized with 21 subjects. Isometric and isokinetic peak torques (Nm) were recorded during maximal voluntary isometric contractions (MVIC) or maximal voluntary contractions (MVC) post-treatment of either SMT or a sham manipulation. The second study incorporated the same experimental design with 20 subjects to examine the effects of SMT on central nervous system (CNS) excitability. This was accomplished by assessing postactivation potentiation (PAP), measured with the Hoffmann Reflex (H-reflex). PAP is an enhanced neuromuscular response to prior contractile activity, and the H-reflex is the electromyographic (EMG) recording of submaximal electrical stimulation of the Ia monosynaptic reflex pathway. Subsequent to SMT and/or a plantar flexion MVIC, EMG amplitudes and isometric twitch torque generation of the gastrocnemius and soleus muscles were recorded during tibial nerve stimulations. The results of the first study indicate that SMT did not produce a significant strength-modulating effect during isometric and isokinetic contractions of neither knee extension nor flexion. Similarly, the second study revealed that SMT immediately preceding the MVIC to induce PAP did not significantly increase H-reflex EMG amplitudes of either muscle or the simultaneous isometric twitch torque generation compared to the MVIC only. These data from both investigations suggest that SMT does not enhance strength or PAP. The positive anecdotal claims of athletes who utilize SMT may be due to other factors, such as the clinical efficacy of the treatment in addressing musculoskeletal injuries or a placebo effect

Limits to temporal synchronization in fundamental hand and finger actions

Coordinated movement is critical not only to sports technique and performance but to daily living and as such represents a fundamental area of research. Coordination requires being able to produce the right actions at the right time and has to incorporate perception, cognition, and forceful neuro-muscular interaction with the environment. Coordinated movements of the hands and fingers are some of the most complex activities undertaken where continuous learning and adaptation take place, but the temporal variability of the most basic movement components is still unknown. This thesis investigates the extent of temporal variability in the execution of four different simple hand and finger coordination tasks, with the purpose to find the various intrinsic temporal variability which limit the ability to coordinate the hands in space and time. Study one showed that in a synchronized bi-lateral two finger tapping test (<<1 cm movement to target) the best participant had a temporaltiming variability of 4.8 ms whereas the largest time variability could be as high as 24.8 ms. No obvious improvement was found after transfer practice, whereas the average time variability for asynchronized tapping decreased from 62.1 ms to 30.3 ms after instructed practice indicating a likely change in task grouping. Study two showed that in a unilateral thumb-index finger pinch and release test, the largest mean timing variability was 12 ms for pinching irrespective of performing the task in a slow alert manner or at a faster speed. However, the mean temporal variability for release was only 6.3 ms when the task was performed in a more alert manner and indicates that release is more accurately controlled temporally than grip. Study three suggested that in a unilateral sagittal plane throwing action of the lower arm and hand, that elbow and wrist coordination for dynamic index finger tip location was better with a radial-ulnar deviation, darts-type, throwing action than a wrist flexor-extensor type action, basketball free throw type action (the mean variability was 37.5 ms and 27.2 ms, respectively). Study four compared the variability in bi-lateral finger tapping between voluntary tapping and involuntary finger contraction tapping. Electrically stimulated neural contractions had significantly lower force onset variability than voluntary or direct magnetic stimulation of muscles (6 ms, 9.5 ms, and 10.3 ms for electrically stimulated, voluntary and Transcranial Magnetic Stimulation stimulated contraction). This work provides a comprehensive analysis of the temporal variability in various fundamental digital movement tasks that can aid with the understanding of basic human coordination in sporting, daily living and clinical areas

Users manual for the Automated Performance Test System (APTS)

The characteristics of and the user information for the Essex Automated Performance Test System (APTS) computer-based portable performance assessment battery are given. The battery was developed to provide a menu of performance test tapping the widest possible variety of human cognitive and motor functions, implemented on a portable computer system suitable for use in both laboratory and field settings for studying the effects of toxic agents and other stressors. The manual gives guidance in selecting, administering and scoring tests from the battery, and reviews the data and studies underlying the development of the battery. Its main emphasis is on the users of the battery - the scientists, researchers and technicians who wish to examine changes in human performance across time or as a function of changes in the conditions under which test data are obtained. First the how to information needed to make decisions about where and how to use the battery is given, followed by the research background supporting the battery development. Further, the development history of the battery focuses largely on the logical framework within which tests were evaluated

ROBOTIC TELESURGERY: AN INVESTIGATION OF UTILITY, HUMAN ADAPTATION, AND PERFORMANCE

Robotic surgery is a powerful, new method for performing minimally invasive surgery (MIS). The method allows complex procedures through incisions which are 10 mm or less. Robotic surgery has grown rapidly because small MIS incisions result in rapid patient recovery compared to conventional methods. Although surgical robots have the potential of long distance control, insufficient data is available to determine whether long distance robotic surgery, or telesurgery, is practical. Telesurgery could provide multiple benefits, including dissemination of expertise, widespread patient care, cost savings, and improved community care. We describe a series of experiments to investigate telesurgery using a one of a kind telesurgery platform and ground- and satellite-based Internet networks. The networks provided the redundancy and quality of service that would be required for human surgery. Tolerances for performing surgical tasks over a long distance were unknown. We show that operators using the platform can complete dry lab manoeuvres with communication latencies up to 500 ms, with no appreciable increase in error rates. Such latency would be equivalent to a North American transcontinental distance, implying a wide range of telesurgical capability. The characteristics of ground- and satellite-based Internet networks for telesurgery were unavailable. We demonstrate that emulated surgery in animals can be effectively performed using either ground or satellite. The networks can reliably support surgery, and satellite-based surgery can be performed even though latency exceeds 500 ms. Further, satellite bandwidth should be above 5 Mb/s for telesurgery applications. Satellite networks could be used either for back up or primarily where a community does not have ground-based equipment. iii Methods of training operators for telesurgery had not been explored. We demonstrate two methods of training for telesurgery. Operators doing dry lab surgical manoeuvres performed equally well either with sequentially increasing latency or with full latency only, suggesting that both methods of training may be effective. Telesurgery can become a practical method of treatment. Within a few years, more widespread platforms and telecommunications may exist to launch everyday telesurgery procedures

Effects of muscle disuse/hospitalization and physical training/retraining on the neuromuscular function in healthy older adults: iso-inertial resistance exercise training as a potential countermeasure form

Population ageing is a global phenomenon and it is causing many concerns regarding the economic, social and health consequences that it might bring to individual countries. Ageing is associated with the decline of the physical performance and the greater risk for the occurrence of physical disabilities. Everyday tasks require good levels of muscle performance, such as muscle force and power abilities. Hence, older people, due to their reduced physical capability levels, might have difficulties in performing these daily actions. Even the walking ability might result impaired in this population which might be associated with a loss in physical independence and, in extreme cases, death. Physical performance deterioration depends on primary ageing processes and lifestyle habits, as well. Within the lifestyle factors, periods of inactivity (i.e. defined as periods where muscles are not stimulated adequately, muscle disuse) are frequent in older people and this might exacerbate performance deterioration in this population. Indeed, muscle disuse causes further impairments in muscle force and power abilities which, added to the intrinsic alterations brought about by ageing processes, might influence everyday tasks to a greater extent. However, influences of muscle disuse on the walking ability in older people are not well studied. Weather muscle disuse can produce negative consequences to this well established and natural motor action in older people is investigated in this thesis. Muscle disuse effects on muscle power and force of the lower limb in older people are studied as well in the current work. Furthermore, to better understand how muscle performance changes with muscle disuse, investigations on the motor control, muscle volume and muscle fibers characteristics accompany the previous analyses. Information about how muscle disuse influences the neuromuscular function of older people might be of clinical importance. Indeed, muscle disuse might be associated to hospitalization periods due to health problems. Interventions that preserve the deterioration of muscle performance before and even after hospitalization might be required to rapidly reintegrate older patients into society. Thus, studying the effects of potential countermeasures, that might be involved before and after hospitalization, on the neuromuscular function of older individuals, is another theme that the current thesis faces. In particular, physical training has been chosen as the promising countermeasure that might help older people to recover from hospitalization or even other muscle disuse periods. As muscle power performance decreases to a greater extent compared to muscle force due to both ageing and muscle disuse conditions, attention is given to a particular form of resistance training: the flywheel iso-inertial resistance training. Although this training has been shown to call for greater muscle power improvements, compared to traditional gravity dependent trainings, its effects on other neuromuscular function features (i.e. muscle force, architecture, etc.) and on the walking ability are not studied in depth. Hence, the current thesis provides new evidence on this topic by further compared it with traditional resistance training adaptations

TRAINING STRATEGIES AND MOVEMENT ASSESSMENTS IN ATHLETES AND NON-ATHLETES

This dissertation is composed of three manuscripts based on two studies related to training and assessment methods used to evaluate change and overall quality in measures of performance, postural control, and functional movement. Study one evaluated the effect of sand training on athletic performance and postural control. Study two investigated the effect of scoring strata of the deep squat (DS) component of the Functional Movement Screen (FMS) on the weight-bearing lunge test (WBLT), Star Excursion Balance Test (SEBT), and Lateral Flexion Test (LFT) in 101 male and female college students. Study one results included significant overall improvements of the five repetition maximum (5RM) squat (p=0.002), and WBLT (p Study two results indicated that limited dorsiflexion will lead to a reduction in DS performance and asymmetry of performance on the LFT may result in further movement limitations. Subjects scoring a one or two on the deep squat performed significantly lower (

Interactions between Manipulation Induced Pain Modulation and Conditioned Pain Modulation Analgesia

The overall objective of this thesis was to improve our understanding of two forms of endogenous analgesia induced by conditioned pain modulation and manipulation induced pain modulation. The studies presented in this thesis have shown a significant association and a comparable increase in CPM and MIPM analgesia in response to enhanced empathetic interaction and aerobic exercise. This suggests that both forms of EA are potentially mediated by a common neuro-physiological mechanism