Physiological and biomechanical responses during high intensity upper body exercise

Fatigue during sport and exercise substantially affects the intensity and duration of an activity that can be maintained. Upper body exercise (UBE) despite contributing to sport, exercise and health outcomes has received relatively little attention particularly for high intensity exercise. Consequently, the mechanisms of fatigue during UBE are not fully understood. Therefore, the aim s of this thesis were to investigate a range of high intensity UBE protocols with respect to performance and the development of fatigue. In the first study participants (n = 13) completed four 30-s Wingate anaerobic tests (WAnT) against four different resistive loadings (2%, 3%, 4% and 5% body mass) thus potentially manipulating force production and cadence. Corrected peak power output (PPO) was independent of load (P > 0.05) and uncorrected PPO increased with load (P 0.05). All participants reached their maximum cardiorespiratory responses (oxygen uptake & heart rate; beats-min'1) at fatigue. The data suggested that prior to Tlim changes in EMG activation and movement patterns were related to the exercise intensity. In general, all EMG activity increased with intensity and exercise duration, with the kinematic data indicating that trunk rotational velocity rather than trunk stabilisation occurred throughout all trials. Overall, untrained participants altered their body movement to maintain PO between 30 & 120 s, however between 120 s & Tlim, no further significant changes occurred. In the final study, participants (n = 12) completed a 6-week arm crank training programme. Preliminary performance tests included a WAnT, V 02peak and 100% PMP test to exhaustion. Each test was repeated following the training programme. Corrected and uncorrected PPO and fatigue index (FI) increased in the WAnT test post training (P < 0.01, P < 0.05, respectively). Muscles of the shoulder (anterior deltoid & infraspinatus) demonstrated reduced activation following training (P < 0.05) with trunk rotational velocity increasing at corrected PPO during the WAnT (P < 0.01). Therefore, increases in WAnT PO may be related to changes in technique rather than muscle activation. Following training there was a significant increase in PMP (P < 0.01) during the V 02peak test and a significant increase in Tlim (P < 0.01) for the repeated 100% PMP test. Following training there was a significant decrease in triceps brachii EMG activation (P < 0.05), changes in external oblique activation (P < 0.001) at 120 s and a significant increase in trunk rotational velocity at 30 s (P < 0.05). Although at Tim, the kinematic responses were the same. The results of this training study indicated that changes in performance were due to physiological adaptations and changes in technique. The three studies have demonstrated the importance of changes in EMG activity, trunk rotational velocity, and technique to arm crank PO rather than specific physiological changes alone which has implications for the use of arm cranking in testing, training and performance outcomes

Recommendations for high intensity upper body exercise testing

Introduction: For given submaximal and maximal peak power outputs aerobic responses to upper body exercise are different to those for lower body exercise (Sawka, 1986: Exercise & Sport Sciences Reviews, 14, 175-211). However, much less is known regarding responses to exercise intensities at and around peak oxygen up take (VO2peak). Purpose: The purpose of this study was to determine the metabolic responses during arm crank ergometry (ACE) below, at and above peak oxygen uptake and to help establish exercise testing guidelines for high intensity upper body exercise. Methods: Following institutional ethical approval fourteen male students (Age 21.1, s = 6.1 years and 2.44 s=0.44 VO2peak) volunteered to take part in this study. Each participant exercised on a table mounted cycle ergometer (Monark 894E, Monark Exercise AB, Sweden). After habituation peak minute power (PMP) was calculated from an incremental test. Subsequently each participant completed four continuous work tests (CWT) to volitional exhaustion at 80%, 90%, 100% and 110% of PMP. All tests were completed at 70 rev∙min-1 with a minimum of 48-h between tests and the order was counterbalanced. Each CWT was preceded by a 5 min warm-up, loaded with a mass corresponding to the participants 80% PMP for 20 s at minutes 2, 3 and 4. Oxygen uptake (VO2), respiratory exchange ratio (RER), heart rate (HR) and ratings of perceived exertion for the arms (local (RPEL) and cardiorespiratory strain (RPECR) were recorded at 1 min, 2 min and at volitional exhaustion. The EMG responses at three sites (flexor carpi ulnaris, biceps brachii and triceps brachii lateral) were recorded using double-differential (16-3000 Hz bandwidth, x300 gain), bipolar, active electrodes (MP-2A, Linton, Norfolk, UK). Electromyographic data were sampled at 1000 Hz and filtered using a 20 to 500 Hz band-pass filter (MP150 Data Acquisition and AcqKnowledge 4.0, Biopac, Goleta, CA). The EMG signals for each muscle were root mean squared (RMS) with a 500-ms sample window. The signal was then normalised, prior to each CWT, as a percentage of the mean of 3 sets of 10 duty cycles completed during the warm-up (see above) when the participants 80% PMP for 20 s was applied. Time to exhaustion (Tlim) was recorded as the performance outcome measure. Data for Tlim were analysed using one-way analysis of variance. Differences in EMG, VO2, RER, HR, RPEL and RPECR were analysed using separate two-way analysis of variance with repeated measures (trial x time). All analyses were performed using the Statistical Package for Social Sciences ( 17.0; SPSS Inc., Chicago, IL). Individual differences in means were located using Bonferroni post-hoc correction. Significance was accepted at P < 0.05. Results: As resistive load increased Tlim decreased (611 s=194, 397 s=99, 268 s=90, 206 s=67s, respectively; P < 0.001, ES = 0.625). Post-hoc analysis revealed that Tlim using 80%PMP was longer than for 90%, 100% and 110% PMP trials (P < 0.001) and 90% was longer than both 100% and 110% PMP trials (P = 0.079, P = 0.001). At exhaustion VO2 was similar across trials (P = 0.413, ES = 0.053), although 80% PMP VO2 tended to be less (2.10 s=0.32 l·min-1) than for 90% (2.29 s=0.37), 100% (2.33 s=0.49) and 110% (2.26 s=0.34). Also, 80% PMP VO2 was less than VO2peak (P = 0.013). There were differences in RER at Tlim (P < 0.001, ES = 0.593) with values increasing with % PMP (1.15 s=0.07, 1.26 s=0.07, 1.36 s=0.10, 1.40 s=0.09, respectively). There were no differences across trials for HR at Tlim (~173 (12); P = 0.834, ES = 0.016) and HR was proportional to %PMP at 1 min, and 2 min. For flexor carpi ulnaris there was an increase in activation as exercise intensity increased (P < 0.001, ES = 0.245). There were a similar responses for biceps brachii and triceps brachii demonstrating an increase in activation with exercise intensity (P <0.001, ES = 0.137, P < 0.001, ES = 0.163, respectively). No differences for RPEL and RPECR were observed at Tlim. Discussion: There was a clear response of Tlim with intensity as expected for lower body exercise (Hill et al., 2002: Medicine and Science in Sports and Exercise, 34(4), 709-714). Despite differences in Tlim across exercise intensities VO2, HR and RPE were similar at exhaustion indicating a functional cardiorespiratory maximum had been reached. As indicated by the RER an increased activation of the anaerobic metabolism with greater exercise intensities (100% and 110%) is likely and therefore this may represent a greater anaerobic component at these two intensities. The increase in EMG activity with intensity could indicate an increase activity with an increase in exercise intensity. Conclusion: It is recommended that due to the combination of muscle activation, oxygen uptake and Tlim that an exercise intensity of 90% or 100% of PMP could be used for high intensity upper body exercise testing

Exercise intensity-dependent effects of arm and leg-cycling on cognitive performance

Physiological responses to arm and leg-cycling are different, which may influence psychological and biological mechanisms that influence post-exercise cognitive performance. The aim of this study was to determine the effects of maximal and submaximal (absolute and relative intensity matched) arm and leg-cycling on executive function. Thirteen males (age, 24.7 ± 5.0 years) initially undertook two incremental exercise tests to volitional exhaustion for arm-cycling (82 ± 18 W) and leg-cycling (243 ± 52 W) for the determination of maximal power output. Participants subsequently performed three 20-min constant load exercise trials: (1) arm-cycling at 50% of the ergometer-specific maximal power output (41 ± 9 W), (2) leg-cycling at 50% of the ergometer-specific maximal power output (122 ± 26 W), and (3) leg-cycling at the same absolute power output as the submaximal arm-cycling trial (41 ± 9 W). An executive function task was completed before, immediately after and 15-min after each exercise test. Exhaustive leg-cycling increased reaction time (p 0.05). Improvements in reaction time following arm-cycling were maintained for at least 15-min post exercise (p = 0.008, d = -0.73). Arm and leg-cycling performed at the same relative intensity elicit comparable improvements in cognitive performance. These findings suggest that individuals restricted to arm exercise possess a similar capacity to elicit an exercise-induced cognitive performance benefit

The influence of 6 weeks of maximal eccentric plantarflexor training on muscle-tendon mechanics

Resistance training can influence muscle-tendon properties including strength, flexibility, stretch tolerance and muscle-tendon stiffness; however the specific influence of eccentric-only training is unknown. Therefore, the aims of the present study were to examine the effects of a 6-week maximal eccentric resistance training programme on isometric plantarflexor moment (MVC), dorsiflexion range of motion (ROM), stretch tolerance (peak passive moment), muscle and tendon stiffness and running economy. Thirteen recreationally active men (age = 20.0 ± 0.9 yr, mass = 75.9 ± 8.5 kg, height = 1.8 ± 0.1 m) volunteered for the study after giving written informed consent; ethical approval was granted from the University of Northampton. Training was performed twice weekly for six weeks and consisted of 5 sets of 12 repetitions of 3-s maximal eccentric contractions at 10°•s-1 from 20° plantarflexion to 10° dorsiflexion. Maximal isometric plantarflexor moment, dorsiflexion ROM, stretch tolerance, and muscle, tendon and muscle-tendon unit (MTU) stiffness were measured using isokinetic dynamometry, real-time ultrasound and 3D motion analyses before and after the training. Running economy (VO2) was determined at a running speed equating to 70%VO2max using online gas analysis. Repeated measures t-tests were used to determine significant differences between pre- and post-training data, significance accepted at p0.05). Analysis of ultrasound data revealed a significant decrease in muscle stiffness (20.6%; p0.05). While the training-induced increase in plantarflexor strength was expected, the substantial increases in ROM, stretch tolerance and tendon stiffness, and the reduction in passive muscle stiffness, were important and novel findings. Interestingly, when measured during passive stretch, MTU stiffness remained unchanged while tendon stiffness increased and muscle stiffness decreased. These disparate findings have clear implications for testing methodologies, and indicate that imaging techniques must be utilised in order to examine the effects of interventions on specific tissues. As the training clearly enhanced the capacity of the muscle to tolerate both tissue loading and deformation, which are commonly associated with muscle strain injury, these data have clear implications for both muscular performance and injury risk

Reviewing the epigenetics of schizophrenia

Background: Epigenetic research in mental health has grown exponentially during the last decade and holds what some claim are “revolutionary” potentials for the development of new interdisciplinary models of mental ill health. Schizophrenia is the most appropriate diagnosis against which to assess progress in this regard. Method: Papers on epigenetics and schizophrenia identified in a systematic literature search are subject to a conceptually-driven narrative review that assesses the relations between schizophrenia and epigenetics; considers some issues associated with empirical studies; and thereby identifies key assumptions guiding this research. Findings: The revolutionary potentials of epigenetics are thus far not being realised due to various influences, including a preponderance of hypotheses that begin from a primarily biological question; the “condensation” of environmental influences and their effective reduction to their molecular consequences; and a frequent reliance upon animal studies that effectively preclude some important influences already established as relevant to this diagnosis. Conclusion: Epigenetic research in schizophrenia (and mental health generally) could benefit from being more thoroughly interdisciplinary, from testing hypotheses that foreground social as well as biological influences, and from reconsidering its reliance upon psychiatric diagnoses

Physiological and biomechanical responses during high intensity upper body exercise

Fatigue during sport and exercise substantially affects the intensity and duration of an activity that can be maintained. Upper body exercise (UBE) despite contributing to sport, exercise and health outcomes has received relatively little attention particularly for high intensity exercise. Consequently, the mechanisms of fatigue during UBE are not fully understood. Therefore, the aim s of this thesis were to investigate a range of high intensity UBE protocols with respect to performance and the development of fatigue. In the first study participants (n = 13) completed four 30-s Wingate anaerobic tests (WAnT) against four different resistive loadings (2%, 3%, 4% and 5% body mass) thus potentially manipulating force production and cadence. Corrected peak power output (PPO) was independent of load (P > 0.05) and uncorrected PPO increased with load (P 0.05). All participants reached their maximum cardiorespiratory responses (oxygen uptake & heart rate; beats-min'1) at fatigue. The data suggested that prior to Tlim changes in EMG activation and movement patterns were related to the exercise intensity. In general, all EMG activity increased with intensity and exercise duration, with the kinematic data indicating that trunk rotational velocity rather than trunk stabilisation occurred throughout all trials. Overall, untrained participants altered their body movement to maintain PO between 30 & 120 s, however between 120 s & Tlim, no further significant changes occurred. In the final study, participants (n = 12) completed a 6-week arm crank training programme. Preliminary performance tests included a WAnT, V 02peak and 100% PMP test to exhaustion. Each test was repeated following the training programme. Corrected and uncorrected PPO and fatigue index (FI) increased in the WAnT test post training (P < 0.01, P < 0.05, respectively). Muscles of the shoulder (anterior deltoid & infraspinatus) demonstrated reduced activation following training (P < 0.05) with trunk rotational velocity increasing at corrected PPO during the WAnT (P < 0.01). Therefore, increases in WAnT PO may be related to changes in technique rather than muscle activation. Following training there was a significant increase in PMP (P < 0.01) during the V 02peak test and a significant increase in Tlim (P < 0.01) for the repeated 100% PMP test. Following training there was a significant decrease in triceps brachii EMG activation (P < 0.05), changes in external oblique activation (P < 0.001) at 120 s and a significant increase in trunk rotational velocity at 30 s (P < 0.05). Although at Tim, the kinematic responses were the same. The results of this training study indicated that changes in performance were due to physiological adaptations and changes in technique. The three studies have demonstrated the importance of changes in EMG activity, trunk rotational velocity, and technique to arm crank PO rather than specific physiological changes alone which has implications for the use of arm cranking in testing, training and performance outcomes

Broadening Responsibilities: Consideration Of The Potential To Broaden The Role Of Uniformed Fire Service Employees

What is this report about? This report, commissioned by the National Joint Council for Local Authority Fire and Rescue Services (NJC), aims to identify what impact, if any, firefighters can have on the delivery of emergency medical response and wider community health interventions in the UK. What are the overall conclusions? Appropriately trained and equipped firefighters co-responding1 to targeted, specific time critical medical events, such as cardiac arrest, can improve patient survival rates. The data also indicate that there is support from fire service staff – and a potential need from members of the public, particularly the elderly, isolated or vulnerable – to expand ‘wider work’. This includes winter warmth assessments, Safe and Well checks, community defibrillator training and client referrals when staff believe someone may have dementia, are vulnerable or even, for example, have substance dependencies such as an alcohol addiction. However, there is currently insufficient data to estimate the net benefit of this work

Optimisation of Raman Spectral Processing for Classification of Radiotherapeutic Toxicity

Severe radiation toxicity can continue years after the completion of radiotherapy for prostate cancer patients. Currently, it is impossible to predict before treatment which patients will experience these long-term side effects. New approaches based on vibrational spectroscopy have advantages over lymphocyte and genomic assays in terms of minimal sample preparation, speed and cost. A high throughput method has been developed to measure Raman spectra from liquid plasma in a cover glass bottomed 96 well plate. However, the Raman spectra can show contributions from glass and water. The current study aims to optimise pre-processing steps to improve classification performance

Belligerent Targeting and the Invalidity of a Least Harmful Means Rule

The law of armed conflict provides the authority to use lethal force as a first resort against identified enemy belligerent operatives. There is virtually no disagreement with the rule that once an enemy belligerent becomes hors de combat — what a soldier would recognizes as “combat ineffective” — this authority to employ deadly force terminates. Recently, however, some have forcefully asserted that the LOAC includes an obligation to capture in lieu of employing deadly force whenever doing so presents no meaningful risk to attacking forces, even when the enemy belligerent is neither physically disabled or manifesting surrender. Proponents of this obligation to capture rather than kill, or use the least harmful means to incapacitate enemy belligerents, do not contest the general authority to employ deadly force derived from belligerent status determinations. Instead, they insist that the conditions that rebut this presumptive attack authority are broader than the traditional understanding of the meaning of hors de combat embraced by military experts, and include any situation where an enemy belligerent who has yet to be rendered physically incapable of engaging in hostilities may be subdued without subjecting friendly forces to significant risk of harm. This essay offers our collective and — we hope — comprehensive rebuttal of this least harmful means LOAC interpretation. First, Section I reviews the fundamental principles of the LOAC that permit status-based attacks against enemy belligerents with combat power highly likely to cause death unless and until the enemy is rendered physically incapable of participating in hostilities. Section II thoroughly analyzes the affirmative prohibitions on the use of force that the LOAC — and specifically Additional Protocol I — does require, and also highlights what Additional Protocol I does not require. In particular, the fact that Additional Protocol I — by any account the most humanitarian-oriented LOAC treaty ever developed — did not impose any affirmative least harmful means obligation vis à vis belligerents undermines any assertion that such an obligation may be derived from the positive LOAC. Finally, and perhaps most importantly, Section III emphasizes how this least harmful means concept, especially when derived from an expanded interpretation of the meaning of the concept of hors de combat, is fundamentally inconsistent with the tactical, operational, and strategic objectives that dictate employment of military power. The LOAC must, as it has historically, remain rationally grounded in the realities of warfare. We are confident that anyone grappling with this issue understands that decisions related to the employment of combat power are not resolved in the quiet and safe confines of law libraries, academic conferences, or even courtrooms; they are resolved in the intensely demanding situations into which our nation thrusts our armed forces. The law must, as it always has, remain animated by the realities of warfare in the effort to strike a continuing credible balance between the authority to prevail on the battlefield and humanitarian objective of limiting unnecessary suffering. The clarity of the existing paradigm achieves that goal and does not include any legal obligation to use the least harmful means in targeting enemy belligerent personnel

The Role of FRMD7 in Idiopathic Infantile Nystagmus

Idiopathic infantile nystagmus (IIN) is an inherited disorder in which the nystagmus arises independently of any other symptoms, leading to the speculation that the disorder represents a primary defect in the area of the brain responsible for ocular motor control. The inheritance patterns are heterogeneous, however the most common form is X-linked. FRMD7 resides at Xq26-27 and approximately 50% of X-linked IIN families map to this region. Currently 45 mutations within FRMD7 have been associated with IIN, confirming the importance of FRMD7 in the pathogenesis of the disease. Although mutations in FRMD7 are known to cause IIN, very little is known about the function of the protein. FRMD7 contains a conserved N-terminal FERM domain suggesting that it may provide a link between the plasma membrane and actin cytoskeleton. Limited studies together with the knowledge of the function of other FERM domain containing proteins, suggest that FRMD7 may play a role in membrane extension during neuronal development through remodeling of the actin cytoskeleton