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1.
Overreaching and overtraining in strength sports and resistance training: A scoping review.
Bell, L, Ruddock, A, Maden-Wilkinson, T, Rogerson, D
Journal of sports sciences. 2020;(16):1897-1912
Abstract
UNLABELLED To date, little is known about overreaching (OR) and the overtraining syndrome (OTS) in strength sports and resistance training (RT) populations. However, the available literature may elucidate the occurrence of both conditions in these populations. A scoping review was conducted. SPORTDiscus, Scopus and Web of Science were searched in a robust and systematic manner, with relevant articles analysed. 1170 records were retrieved during an initial search, with a total of 47 included in the review. Two broad themes were identified during data extraction: 1) overreaching in strength sports; 2) overreaching and overtraining syndrome in RT. Short-term periods of OR achieved with either high-volume or high-intensity RT can elicit functional OR (FOR) but there is also evidence that chronic high-volume and/or intensity RT can lead to non-functional overreaching (NFOR). There is minimal evidence to suggest that true OTS has occurred in strength sports or RT based on the studies entered during this review. More research is needed to develop robust guiding principles for practitioners. Additionally, due to the heterogeneous nature of the existing literature, future research would benefit from the development of practical tools to identify and diagnose the transition from FOR to NFOR, and subsequently OTS in strength athletes and RT populations. ABBREVIATIONS RT: Resistance training; OR: Overreaching; FOR: Functional overreaching; NFOR Non-functional overreaching; OTS: Overtraining syndrome; WP: Weightlifting performance.
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2.
Plantar pressure measurements and running-related injury: A systematic review of methods and possible associations.
Mann, R, Malisoux, L, Urhausen, A, Meijer, K, Theisen, D
Gait & posture. 2016;:1-9
Abstract
Pressure-sensitive measuring devices have been identified as appropriate tools for measuring an array of parameters during running. It is unclear which biomechanical characteristics relate to running-related injury (RRI) and which data-processing techniques are most promising to detect this relationship. This systematic review aims to identify pertinent methodologies and characteristics measured using plantar pressure devices, and to summarise their associations with RRI. PubMed, Embase, CINAHL, ScienceDirect and Scopus were searched up until March 2015. Retrospective and prospective, biomechanical studies on running using any kind of pressure-sensitive device with RRI as an outcome were included. All studies involving regular or recreational runners were considered. The study quality was assessed and the measured parameters were summarised. One low quality, two moderate quality and five high quality studies were included. Five different subdivisions of plantar area were identified, as well as five instants and four phases of measurement during foot-ground contact. Overall many parameters were collated and subdivided as plantar pressure and force, plantar pressure and force location, contact area, timing and stride parameters. Differences between the injured and control group were found for mediolateral and anteroposterior displacement of force, contact area, velocity of force displacement, relative force-time integral, mediolateral force ratio, time to peak force and inter-stride correlative patterns. However, no consistent results were found between studies and no biomechanical risk patterns were apparent. Additionally, conflicting findings were reported for peak force in three studies. Based on these observations, we provide suggestions for improved methodology measurement of pertinent parameters for future studies.
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3.
Determination of muscle activity during running at reduced body weight.
Liebenberg, J, Scharf, J, Forrest, D, Dufek, JS, Masumoto, K, Mercer, JA
Journal of sports sciences. 2011;(2):207-14
Abstract
The aim of this study was to investigate how lower extremity muscles are influenced by body weight support during running at different speeds. Nine participants (age 24 ± 2 years, height 1.75 ± 0.12 m, mass 73.5 ± 15.7 kg) ran at 100%, 115%, and 125% of preferred speed at 100%, 90%, 80%, 70%, and 60% of body weight on a treadmill that provided body weight support. Preferred speed was self-selected by each participant and represented a speed that he or she could sustain if going for a 30 min run. Electromyography (EMG) data were recorded (1000 Hz, 1 min) from the bicep femoris, rectus femoris, tibialis anterior, and gastrocnemius for each condition together with knee angle (electrogoniometer). Average and root mean square EMG were calculated across 30 s. Muscle patterns were determined by smoothing (low-pass filter, 4 Hz) and extracting patterns for 49 cycles defined by consecutive maximum knee flexion angles. Repeated-measures analyses of variance were used to compare average and root mean square across body weight and speeds. Correlations were computed between the 100% speed/100% body weight condition and all other conditions per muscle. There was no interaction between body weight and speed (P > 0.05). Average and root mean square decreased as body weight decreased for all muscles (P < 0.05) and increased across speeds for all muscles (P < 0.05). Correlations for all muscles between conditions were high (range: 0.921-0.999). Although a percent reduction in body weight did not lead to the same reduction in muscle activity, it was clear that reducing body weight leads to a reduction in muscle activity with no changes in muscle activity patterns.
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4.
Dissociation in changes in EMG activation during maximal isometric and submaximal low force dynamic contractions after exercise-induced muscle damage.
Plattner, K, Baumeister, J, Lamberts, RP, Lambert, MI
Journal of electromyography and kinesiology : official journal of the International Society of Electrophysiological Kinesiology. 2011;(3):542-50
Abstract
Exercise induced muscle damage (EIMD) is characterized by muscle pain, symptoms of swelling, muscle shortening, increased serum creatine kinase activity, decreased force output and altered neuromuscular function. The aim of this study was to determine how the symptoms of EIMD influence the neuromuscular recruitment patterns during maximal and submaximal isometric and submaximal flexion-extension movements. Twenty-five right-handed males were recruited for this study, and were allocated to a control (n=13) or experimental group (n=12). In contrast to the control group, the experimental group participated in an EIMD protocol. Subsequently, symptoms of both groups were closely monitored for 132 h. After the EIMD protocol, muscle pain scores in the experimental group peaked after 36 h with creatine kinase activity peaking after 108 h. Twelve hours after the EIMD protocol, EMG activity had decreased by 20% during a maximal voluntary contraction in the experimental group and decreased by a further 10% until the end of the study was reached 132 h after the EIMD protocol. In contrast EMG during a submaximal flexion-extension movement increased significantly until the end of the study (132h). This dissociated EMG activity at submaximal and maximal intensity, suggests that central regulation influences the neural firing patterns and motor unit activity.
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5.
Effectiveness of an ergonomic intervention on the productivity of workers with upper-extremity disorders--a randomized controlled trial.
Martimo, KP, Shiri, R, Miranda, H, Ketola, R, Varonen, H, Viikari-Juntura, E
Scandinavian journal of work, environment & health. 2010;(1):25-33
Abstract
OBJECTIVES The aim of this study was to investigate the effectiveness of an ergonomic intervention on productivity loss at work caused by upper-extremity disorders (UED). METHODS Workers with medically verified UED were invited to participate. The intervention consisted of a physician contacting the worker's supervisor and an occupational physiotherapist conducting an ergonomic assessment at the worksite. Before and after the intervention, the employees self-assessed UED-related productivity loss (ie, decreased quality and quantity of the daily work output). We tested for differences between groups at 8 and sub-sequently 12 weeks. We also applied generalized estimating equation (GEE) to analyze repeated measures data. RESULTS Altogether 177 employees were randomized. The overall participation rate was 88%. At baseline, 54% of the intervention group and 58% of the control group reported productivity loss. The magnitude of productivity loss was 17% and 20%, respectively. At 8 weeks, both the proportion and magnitude of productivity loss were lower in the intervention than the control group, but the differences were statistically significant only at 12 weeks (proportion 25% versus 51%, magnitude 7% versus 18%, P=0.001 for both). Using GEE analyses, we also found the differences to be statistically significant (proportion 38% versus 52%, magnitude 12% versus 18%). The intervention only benefitted employees with 0-20% loss of productivity at baseline, not those with a higher initial productivity loss. CONCLUSIONS Early ergonomic intervention, in addition to adequate medical care, is effective in preventing and restoring self-reported productivity loss associated with UED.
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6.
New aspects of the hormone and cytokine response to training.
Steinacker, JM, Lormes, W, Reissnecker, S, Liu, Y
European journal of applied physiology. 2004;(4):382-91
Abstract
Exercise training is associated with peripheral-cellular and central-cerebral processes, hormonal-neuronal regulation and transmission mechanisms. During the acute training response, peripheral cellular mechanisms are mainly metabolostatic to achieve energy supply and involve associated cytokine and hormonal reactions. Glycogen deficiency is associated with increased expression of local cytokines (interleukin-6, IL-6), decreased expression of glucose transporters, increased cortisol and decreased insulin secretion and beta-adrenergic stimulation. A nutrient-sensing signal of adipose tissue may be represented by leptin which, as for insulin, IL-6 and insulin-like growth-factor I (IGF-I), has profound effects on the hypothalamus and is involved in the metabolic hormonal regulation of exercise and training. Muscle damage and repair processes may involve the expression of inflammatory cytokines (e.g. tumour necrosis factor-alpha, TNF-alpha) and of stress proteins (e.g. heat shock protein 72). During overreaching and overtraining, a myopathy-like state is observed in skeletal muscle with depressed turnover of contractile proteins (e.g. in fast-type glycolytic fibres with a concomitant increase in slow type myosins). These alterations are influenced by exercise-induced hypercortisolism, and by decreased somatotropic hormones (e.g. IGF-I). The hypothalamus integrates various error signals (metabolic, hormonal, sensory afferents and central stimuli) and therefore pituitary releasing hormones represent the functional status of an athlete and long-term hypothalamic hormonal and sympathoadrenal downregulation are some of the prominent hormonal signs of prolonged overtraining and performance incompetence syndrome.
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7.
Reactive oxygen species and tendinopathy: do they matter?
Bestwick, CS, Maffulli, N
British journal of sports medicine. 2004;(6):672-4
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8.
Relationship between stress and pain in work-related upper extremity disorders: the hidden role of chronic multisymptom illnesses.
Clauw, DJ, Williams, DA
American journal of industrial medicine. 2002;(5):370-82
Abstract
BACKGROUND Pain and fatigue are commonly associated with work-related upper extremity disorders. Occasionally these symptoms persist beyond a reasonable healing period. One potential explanation for prolonged symptom expression is the concurrent development of a stress-mediated illness or CMI (Chronic Multi-Symptom Illness). In such a scenario, the chronic regional pain and other symptoms that the individual is experiencing would be attributable to the CMI rather than to tissue damage or a biomechanical dysfunction of the upper-extremity. METHODS This article critically reviews the case definitions of the new class of CMI disorders and evaluates the existing evidence supporting centrally mediated physiological changes (e.g., sensory hypervigilance, dysautonomia) that manifest as symptoms of pain and fatigue in some individuals experiencing chronic stressors. RESULTS While explanations for prolonged pain and fatigue have historically focused on mechanisms involving peripheral pathology or psychiatric explanations, ample evidences support the role of altered Central Nervous System function in accounting for symptom manifestation in CMI. CONCLUSIONS A model is presented that unites seemingly disparate findings across numerous investigations and provides a framework for understanding how genetics, triggering events, stressors, and early life events can affect CNS activity. Resultant symptom expression (e.g., pain and fatigue) from central dysregulation would be expected to occur in a subset of individuals in the population, including a subset of individuals with work-related upper extremity disorders. Thus when symptoms such as pain and fatigue persist beyond a reasonable period, consideration of CMI and associated assessment and interventions focused on central mechanisms may be worthwhile.