Muscular Stress Research Articles

Jaw exercises and awareness as a minimally invasive and adjunctive modality to help relieve the stress on the TMJ and tension headaches due to bruxism

Dr. Dana G. Colson, in reference to her book, Your Mouth: The Gateway to a Healthier You explores the dental origins of headaches, the importance of patient education and the prescription of minimally invasive techniques in order to relieve muscular stress and tension headaches caused by bruxism. A yoga based approach including jaw exercises allows for integration with dental practices to ensure overall wellness.

Development and experimental verification of an ergonomic shopping bag handle.

Plastic shopping bags are used world over. However, users may suffer pain in or injury to their fingers because of the relatively thin plastic handles of those bags. Due to such drawbacks of the available bag handles, new designs are needed. The purpose of this study was to develop a handle that can be used to carry many bags simultaneously. This handle was ergonomically designed and manufactured with soft grip. Then, an experiment was performed to test the usefulness of the developed handle. The cardiac cost, discomfort ratings, activity levels of eight muscles, and peak plantar pressure (PPP) were the response variables in the experiment. The carrying style (with or without the handle), carrying method (dominant hand or both hands), and weight carried (5%, 10%, or 15% of the subject's body weight) were the independent variables in the experiment. Twenty-six healthy, young volunteers participated in the experiment. It was found that carrying grocery bags in both hands using the bag handle was preferable to the other carrying methods because it reduced the cardiac cost, muscular stress, PPP, and average discomfort ratings. The results of this study demonstrated that the developed shopping bag handle provides an ergonomic solution for carrying multiple heavy plastic bags.

DMD TREATMENT: ANIMAL MODELS: P.211Myostatin inhibition and growth factor treatment of pre- and post-disease onset mdx mice does not improve the phenotype coherently

Muscular dystrophies are genetic disorders compromising muscular function and leading to muscular wasting. While several clinical trials have been testing safety and efficacy on promising treatments, no cure exists yet. In the past 15 years myostatin, a negative regulator of muscular mass, has been a major focus of treatment development as mice treated with myostatin inhibitors got larger muscles. Clinical trials have, however, not yet demonstrated a significant ameliorating effect of myostatin inhibition in patients with muscular dystrophy. In order to investigate if myostatin inhibition treatment could be improved by concurrently boosting the muscle regeneration with growth factors we treated 4-week (pre-onset) and 8-week (post-onset) old cohorts of the Duchenne muscular dystrophy mouse model, mdx, with myostatin inhibitor alone, with a growth factor cocktail and with the growth factor cocktail alone once a week for 12 weeks, while monitoring the body weight. At the end of treatment, isometric and eccentric force contraction ex vivo in extensor digitorum longus (EDL) and soleus was determined. The muscular mass was generally bigger in the treatment groups receiving myostatin inhibition with and without growth factors, but specific force overall did not improve. Treatment of post-onset mice demonstrated an improvement of muscular stress resistance compared to controls. Overall, there was no significant overall effect of the treatments, regardless of type and age initiated, compared to controls. These findings in the mdx mice, and absence of clinical improvement in human clinical trials, suggest that treating DMD by means of myostatin inhibition should be re-evaluated.

Relation Between Training Load and Recovery-Stress State in High-Performance Swimming.

Background: The relation between training load, especially internal load, and the recovery-stress state is of central importance for avoiding negative adaptations in high-performance sports like swimming. The aim of this study was to analyze the individual time-delayed linear effect relationship between training load and recovery-stress state with single case time series methods and to monitor the acute recovery-stress state of high-performance swimmers in an economical and multidimensional manner over a macro cycle. The Acute Recovery and Stress Scale (ARSS) was used for daily monitoring of the recovery-stress state. The methods session-RPE (sRPE) and acute:chronic workload-ratio (ACWR) were used to compare different methods for quantifying the internal training load with regard to their interrelationship with the recovery-stress state.Methods: Internal load and recovery-stress state of five highly trained female swimmers [with a training frequency of 13.6 ± 0.8 sessions per week and specializing in sprint (50 and 100 m), middle-distance (200 and 400 m), or long distance (800 and 1,500 m) events] were daily documented over 17 weeks. Two different types of sRPE were applied: RPE∗duration (sRPEh) and RPE∗volume (sRPEkm). Subsequently, we calculated the ratios ACWRh and ACWRkm (sRPE last week: 4-week exponentially weighted moving average). The recovery-stress state was measured by using the ARSS, consisting of eight scales, four of which are related to recovery [Physical Performance Capability (PPC), Mental Performance Capability (MPC), Emotional Balance (EB), Overall Recovery (OR)], and four to stress [Muscular Stress (MS), Lack of Activation (LA), Negative Emotional State (NES), Overall Stress (OS)]. To examine the relation between training load and recovery-stress state a cross correlation (CCC) was conducted with sRPEh, sRPEkm, ACWRh, and ACWRkm as lead and the eight ARSS-scales as lag variables.Results: A large variation of training load can be observed in the individual week-to-week fluctuations whereby the single fluctuations can significantly differ from the overall mean of the group. The range also shows that the CCC individually reaches values above 0.3, especially with sRPEkm as lead variable. Overall, there is a large range with significant differences between the recovery and stress dimensions of the ARSS and between the training load methods, with sRPEkm having the largest span (Range = 1.16). High inter-individual differences between the athletes lie in strength and direction of the correlation | 0.66|≤ CCC ≥|-0.50|. The time delayed effects (lags 0–7) are highly individual, however, clear patterns can be observed.Conclusion: The ARSS, especially the physical and overall-related scales (PPC, OR, MS, OS), is a suitable tool for monitoring the acute recovery-stress state in swimmers. MPC, EB, LA, and NES are less affected by training induced changes. Comparably high CCC and Ranges result from the four internal load methods, whereby sRPE, especially sRPEkm, shows a stronger relation to recovery-stress state than ACWR. Based on these results and the individual differences in terms of time delay in training response, we recommend for swimming to use sRPE to monitor the internal training load and to use the ARSS, with a focus at the physical and overall-scales, to monitor the recovery-stress state.

Ergonomic evaluation of subjects involved in orange (<i>Citrus sinensis</i>) handling operations in Yanlemo Market Kano State

Ergonomic evaluation of subjects involved in orange handling operation in Kano State was conducted. Anthropometric parameters were evaluated, where they were found to vary with age amongst the subjects selected. 20th and 80th percentiles of the dimensions were computed and recommended for usage in design of the relevant orange handling equipment. To evaluate the Physiological parameters, sorting/grading operations and washing operations were selected for this study. Results obtained revealed that, heart beat rate, oxygen consumption and energy expenditure varied amongst the subjects with age. Muscular stress and postural disorder were also studied. Comparing the parameters obtained during sorting/grading operation and that obtained during washing operations revealed that orange operations resulted to superior drudgery and musculoskeletal disorders.Keywords: Anthropometrics, Energy expenditure, Drudgery, Operations and Musculoskeletal disorder

Comparative assessment of grain picking activity using existing and improved grain picking tool

Filling of cleaned grains in gunny bags for storage is one of the post-harvest operation which requires human physical efforts. Labourers while filling gunny bags with grains, using traditional tool, have to put in more efforts which results in lower output and increased time consumption. More number of repetitive motions also causes various musculoskeletal disorders (MSDs). The present study was, therefore, planned with an aim to test the efficiency of an improved tool, grain picker, designed and developed by department of FRM, G.B. Pant University of Agriculture and Technology, Pantnagar in terms of reduction in muscular stresses and increase in work efficiency. The study was conducted on 15 randomly selected workers of grain market in Mullanpur town of Ludhiana district. Results revealed that improved tool, grain picker, enhanced work efficiency and increased work output. Hand grip fatigue was also reduced after working with improved tool.

Downhill exercise alters immunoproteasome content in mouse skeletal muscle.

Content of the immunoproteasome, the inducible form of the standard proteasome, increases in atrophic muscle suggesting it may be associated with skeletal muscle remodeling. However, it remains unknown if the immunoproteasome responds to stressful situations that do not promote large perturbations in skeletal muscle proteolysis. The purpose of this study was to determine how an acute bout of muscular stress influences immunoproteasome content. To accomplish this, wild-type (WT) and immunoproteasome knockout lmp7 -/- /mecl1 -/- (L7M1) mice were run downhill on a motorized treadmill. Soleus muscles were excised 1 and 3days post-exercise and compared to unexercised muscle (control). Ex vivo physiology, histology and biochemical analyses were used to assess the effects of immunoproteasome knockout and unaccustomed exercise. Besides L7M1 muscle being LMP7/MECL1 deficient, no other major biochemical, histological or functional differences were observed between the control muscles. In both strains, the downhill run shifted the force-frequency curve to the right and reduced twitch force; however, it did not alter tetanic force or inflammatory markers. In the days post-exercise, several of the proteasome's catalytic subunits were upregulated. Specifically, WT muscle increased LMP7 while L7M1 muscle instead increased β5. These findings indicate that running mice downhill results in subtle contractile characteristics that correspond to skeletal muscle injury, yet it does not appear to induce a significant inflammatory response. Interestingly, this minor stress activated the production of specific immunoproteasome subunits that if knocked out were replaced by components of the standard proteasome. These data suggest that the immunoproteasome may be involved in maintaining cellular homeostasis.

High-intensity high-volume swimming induces more robust signaling through PGC-1α and AMPK activation than sprint interval swimming in m. triceps brachii.

We aimed to test whether high-intensity high-volume training (HIHVT) swimming would induce more robust signaling than sprint interval training (SIT) swimming within the m. triceps brachii due to lower metabolic and oxidation. Nine well-trained swimmers performed the two training procedures on separate randomized days. Muscle biopsies from m. triceps brachii and blood samples were collected at three different time points: a) before the intervention (pre), b) immediately after the swimming procedures (post) and c) after 3 h of rest (3 h). Hydroperoxides, creatine kinase (CK), and lactate dehydrogenase (LDH) were quantified from blood samples, and peroxisome proliferator-activated receptor γ coactivator 1α (PGC-1α) and the AMPKpTHR172/AMPK ratio were quantified by Western blot analysis. PGC-1α, sirtuin 3 (SIRT3), superoxide-dismutase 2 (SOD2), and vascular endothelial growth factor (VEGF) mRNA levels were also quantified. SIT induced a higher release of LDH (p < 0.01 at all time points) and CK (p < 0.01 at post) than HIHVT, but neither SIT nor HIHVT altered systemic hydroperoxides. Additionally, neither SIRT3 nor SOD2 mRNA levels increased, while PGC-1α transcription increased at 3 h after SIT (p < 0.01) and after HIHVT (p < 0.001). However, PGC-1α protein was higher after HIHVT than after SIT (p < 0.05). Moreover, the AMPKpTHR172/AMPK ratio increased at post after SIT (p < 0.05), whereas this effect was delayed after HIHVT as it increased after 3 h (p < 0.05). In addition, VEGF transcription was higher in response to HIHVT (p < 0.05). In conclusion, SIT induces higher muscular stress than HIHVT without increasing systemic oxidation. In addition, HIHVT may induce more robust oxidative adaptations through PGC-1α and AMPK.

Blood flow restricted training leads to myocellular macrophage infiltration and upregulation of heat shock proteins, but no apparent muscle damage.

Muscular contractions performed using a combination of low external loads and partial restriction of limb blood flow appear to induce substantial gains in muscle strength and muscle mass. This exercise regime may initially induce muscular stress and damage; however, the effects of a period of blood flow restricted training on these parameters remain largely unknown. The present study shows that short-term, high-frequency, low-load muscle training performed with partial blood flow restriction does not induce significant muscular damage. However, signs of myocellular stress and inflammation that were observed in the early phase of training and after the training intervention, respectively, may be facilitating the previously reported gains in myogenic satellite cell content and muscle hypertrophy. The present results improve our current knowledge about the physiological effects of low-load muscular contractions performed under blood flow restriction and may provide important information of relevance for future therapeutic treatment of muscular atrophy. Previous studies indicate that low-load muscle contractions performed under local blood flow restriction (BFR) may initially induce muscle damage and stress. However, whether these factors are evoked with longitudinal BFR training remains unexplored at the myocellular level. Two distinct study protocols were conducted, covering 3weeks (3wk) or one week (1wk). Subjects performed BFR exercise (100mmHg, 20% 1RM) to concentric failure (BFRE) (3wk/1wk), while controls performed work-matched (LLE) (3wk) or high-load (HLE; 70% 1RM) (1wk) free-flow exercise. Muscle biopsies (3wk) were obtained at baseline (Pre), 8days into the intervention (Mid8), and 3 and 10days after training cessation (Post3, Post10) to examine macrophage (M1/M2) content as well as heat shock protein (HSP27/70) and tenascin-C expression. Blood samples (1wk) were collected before and after (0.1-24h) the first and last training session to examine markers of muscle damage (creatine kinase), oxidative stress (total antibody capacity, glutathione) and inflammation (monocyte chemotactic protein-1, interleukin-6, tumour necrosis factor α). M1-macrophage content increased 108-165% with BFRE and LLE at Post3 (P<0.05), while M2-macrophages increased (163%) with BFRE only (P<0.01). Membrane and intracellular HSP27 expression increased 60-132% at Mid8 with BFRE (P<0.05-0.01). No or only minor changes were observed in circulating markers of muscle damage, oxidative stress and inflammation. The amplitude, timing and localization of the above changes indicate that only limited muscle damage was evoked with BFRE. This study is the first to show that a period of high-frequency, low-load BFR training does not appear to induce general myocellular damage. However, signs of tissue inflammation and focal myocellular membrane stress and/or reorganization were observed that may be involved in the adaptation processes evoked by BFR muscle exercise.

Impact of Downhill Running on Proteasome Content in Mouse Skeletal Muscle

PURPOSE: The proteasome consists of two main forms, the standard proteasome and its inducible counterpart, the immunoproteasome. In skeletal muscle, the standard proteasome is responsible for myofibrillar protein degradation while the immunoproteasome generates antigenic peptides for immune surveillance. The standard proteasome and immunoproteasome both increase in content and activity following catabolic conditions, such as aging and denervation. However, little is known about how the proteasome responds to stressful conditions that do not promote large perturbations in skeletal muscle proteolysis. Therefore, the purpose of this study was to assess proteasome content following a single session of acute muscular stress. METHODS: Male C57BL/6 wild type (WT) and immunoproteasome knockout lmp7−/−/mecl-1−/− (L7M1) mice ran on a motorized treadmill at a 22 degree decline for 70 min. Soleus muscles were then excised one and three days post-exercise and compared to muscle that did not exercise (baseline). Whole muscle ex vivo physiology, histology and biochemical analyses were used to assess the effects of immunoproteasome knockout and downhill running. TNF-α and MCP-1 levels were evaluated with ELISAs while immunoblots were used to quantify standard proteasome (19S, β1, β5) and immunoproteasome (11S, LMP7, MECL-1) content, and global levels of protein carbonylation. RESULTS: When compared to baseline, the bout of downhill running reduced twitch force one day post-exercise, indicative of low-frequency fatigue. However, it did not significantly depress tetanic force or alter the amount of TNF-α, MCP-1 or carbonylated proteins present in the muscle. Besides L7M1 muscle lacking LMP7 and MECL-1, no other differences in proteasome content were observed at baseline. In contrast, following the exercise, WT muscle tended to upregulate the catalytic subunits of the immunoproteasome while L7M1 muscle instead upregulated the catalytic subunits of the standard proteasome. CONCLUSIONS: Together, these results suggest that downhill running does not significantly alter tetanic force production or induce a large inflammatory response in mouse soleus muscle. Yet, it appears the stress of downhill running activates the production of specific subunits of the proteasome, of which are influenced by LMP7 and MECL-1.

SPATIAL ANALYSIS ON HEALTH PROBLEMS AMONG UNORGANIZED INDUSTRIAL WORKERS IN AMBEDKARNAGAR DISTRICT, INDIA

Health status is one of the important indicators for the welfare of people. People working in unorganized sector are exploited in terms of working hours, low and irregular income, unsatisfactory work conditions, no legal protection and exposed to occupational health hazards. Present study aims to analyze a spatial dimension of occupational health outcomes among the cottage industry workers and their socioeconomic conditions. Based on field survey, the result shows that there is an association between different categories of industries and various health problems which leads respiratory and muscular problem, skin disease, and stress and sleep disturbances. There should be a strong provision for occupational health services, carrying out activities in the work place in the aim of protecting and promoting worker’s safety, health and well-being.

Low Cadence, High Resistance Creates More Muscle Breakdown than High Cadence, Low Resistance in Well Trained Cyclists during High Intensity Interval Training

Purpose: Research by Laursen (2005:Journal of Strength and Conditioning Research, 19, 527-533) demonstrated the positive effects of High Intensity Interval Training on cycling performance concluding that peripheral (muscular) adaptations were the likely cause of increase in performance. Research also shows the relationship between cadence and gross efficiency in cycling (Ansley, 2009: European Journal of Sport Science, 9, 61-85) however there is no research to determine whether a cadence that has been deemed ‘efficient’ (least metabolic cost) produces an optimal training stimulus (measured as the breakdown of muscle). This research sought to provide cyclists and coaches insight into how they can manipulate cadence during HIIT to obtain a desired acute training response.  Methods: 7 well trained cyclists who compete at least 10 times per year and can sustain at least 4.0 watts per kilogram at maximal aerobic power underwent a high intensity interval training (HIIT) protocol where they maintained 125% Functional Threshold Power (381 ± 56 W) for 40 seconds followed by 20 seconds recovery in a set of 10 repetitions. The participants repeated the test at 3 different cadences, 70, 90 and 110 revolutions per minute (RPM) with at least a 24 hour gap between tests. Before each test, creatine kinase (CK) levels were measured at baseline and immediately at the end of the test. Participants were asked to grade each workout on the pain they felt in their legs on a visual analogue scale (VAS) as well as score a representative perceived effort (RPE) score to represent their overall feeling of effort on every second interval.  Results: Significant difference (p = 0.038) in creatine kinase measurements before and after all the HIIT protocols. The paired T-tests reveal that the difference lies between the 70 and 90RPM protocols (p=.040) with the mean (+48.85) indicating that 70RPM produced the greatest increase in CK levels. There were no significant differences in RPE between the different cadences at any point during the tests: 2 minutes (p=.956), 4 minutes (p=.878), 6 minutes (p=.304), 8 minutes (p=.199) and 10 minutes (p=.140). There were no significant differences between protocols in relation to VAS scores: 2 minutes (p=.325), 4 minutes (p=. 247), 6 minutes (p=.382), 8 minutes (p=.326) and 10 minutes (p=.304) suggesting that the participants did not deem any particular cadence to provide a greater sensation of workload.  Conclusion: A study by Formenti et al (2015: Physiological Reports, 3, 1-10) considered the validity of the American College of Sports Medicine recommended equation for calculating work rate (power) on a cycle ergometer in relation to cadence. The study presented the notion that given a 6 metre distance per pedal revolution, whether an individual pedals at a resistance of about 53 N (product of resistance) and cadence of 30 RPM, or at a resistance of about 13 N and cadence of 120 RPM, the equation would present exactly the same work rate of 160 W, whereas the two physiological responses to exercise would be very different. This research has found there to be an advantage to conducting HIIT at a lower cadence with an increased resistance at 125% of FTP in order to provide greater muscle breakdown in well trained cyclists. This concurs with Ansley et al (2009) who established there to be a difference in gross efficiency when cycling at different cadences in relation to muscular stress, energetic cost and perceived effort however unlike Ansley et al this research found no difference in perceived exertion between the cadences. Although this research has not taken any measurements of energetic/metabolic cost of different cadences, existing research studies (Brisswater, 2000: International Journal of Sports Medicine, 21, 60-64) have been presented within this area and demonstrate a higher metabolic cost to cycling at a higher cadence.

Orthognathic surgery: the incisor decompensation and its effect on articulation

The surgical protocols are based on arches preparation before or immediately after the surgical phase. Incisor guides normalization is achieved by incisor decompensation in three dimensions. Place and extend of surgical movements depend on the incisor position obtained at the end of orthodontic preparation. Extraction versus non extraction depends on incisor position planning. Orthognathic surgery induces muscular and temporo-mandibular joint stress which can cause temporo mandibular dysfunction (TMD). This article studies relations between incisor decompensation amplitude, orthognathic surgical procedures and risk to create or to increase TMD. Sagittal, vertical and transversal incisor decompensation impact to place and amplitude of surgical movements. Incisor decompensation does not seem to induce TMD during orthodontic preparation even if occlusal guide controls are lost. Temporo mandibular dysfunction degrees define surgical movements area, moderate specially mandibular surgical movements and incisor decompensation objectives.

Biochemical assessment of oxidative stress by the use of açai (Euterpe oleracea Martius) gel in physically active individuals

The relation between oxidative stress and inflammation induced by diseases and exercise has increased the interest in the benefits of antioxidant supplements in the improvement of health and physical and mental performance. The aim of this study was to evaluate the effectiveness of acai gel in reducing oxidative stress in individuals engaged in physical activities as well as their acceptance. Sensory evaluation was performed to determine its acceptability and the biochemical parameters related to immune profile and biomarkers of muscle, liver and oxidative stress, with and without the use of gel were evaluated. The appearance, sweetness and overall impression of the acai gel were considered good. It was observed a significant increase in CK enzyme, without the gel as well as the oxidative stress biomarkers, it was observed that the MDA (with and without gel) a significant increase (p < 0.05). Through biochemical evaluation, it is concluded that the gel provided protection for some of parameters studied, since it modulated the immunological parameter reducing the lymphocyte activity and muscular stress. However, more studies must be carried out with a larger number of individuals to confirm the gel functionality.

Effects of mouse slant and desktop position on muscular and postural stresses, subject preference and performance in women aged 18–40 years

This study compared muscular and postural stresses, performance and subject preference in women aged 18–40 years using a standard mouse, a vertical mouse and a slanted mouse in three different computer workstation positions. Four tasks were analysed: pointing, pointing-clicking, pointing-clicking-dragging and grasping-pointing the mouse after typing. Flexor digitorum superficialis (FDS) and extensor carpi radialis (ECR) activities were greater using the standard mouse compared to the vertical or slanted mouse. In all cases, the wrist position remained in the comfort zone recommended by standard ISO 11228-3. The vertical mouse was less comfortable and more difficult to use than the other two mice. FDS and ECR activities, shoulder abduction and wrist extension were greater when the mouse was placed next to the keyboard. Performance and subject preference were better with the unrestricted mouse positioning on the desktop. Grasping the mouse after typing was the task that caused the greatest stress.Practitioner Summary: In women, the slanted mouse and the unrestricted mouse positioning on the desktop provide a good blend of stresses, performance and preference. Unrestricted mouse positioning requires no keyboard, which is rare in practice. Placing the mouse in front of the keyboard, rather than next to it, reduced the physical load.

Prevalence of Neck Pain among School Teachers and its Association with Perceived Muscular Tension, Job Stress and Physical Exposure; An Observational Study

Prevalence of Neck Pain among School Teachers and its Association with Perceived Muscular Tension, Job Stress and Physical Exposure; An Observational Study

Effectiveness of psychological training combined ‎with gradual muscular stress relaxation technique on quality of life of patients with multiple sclerosis

Effectiveness of psychological training combined ‎with gradual muscular stress relaxation technique on quality of life of patients with multiple sclerosis

Spontaneous Septic Arthritis of Pubic Symphysis in an Elite Athlete.

Septic arthritis of the pubic symphysis is a potentially severe disease. Athletes are at risk of this form of spontaneous arthritis, as inflammation of the pubic bone due to muscular stress is relatively common. Oedema due to inflammation might predispose to infection through bacteraemia or local bacterial translocation. Suspicion should be raised when an athlete complains of groin pain and has signs of infection (i.e., fever, elevated white blood cell count, and elevated C-reactive protein). Diagnosis is made by imaging showing signs of inflammation combined with positive (blood) cultures. Broad spectrum antibiotics should be started upon suspicion and adjusted according to cultures. An abscess causing clinical deterioration under antibiotic treatment is an indication for invasive intervention (i.e., surgical or image-guided drainage). This is the first case of spontaneous septic arthritis of the pubic symphysis in an athlete requiring surgical and additional image-guided drainage.

The acute muscular effects of cycling with and without different degrees of blood flow restriction.

The aim was to compare the acute effects of work matched high intensity (75% peak aerobic capacity) aerobic exercise to low intensity (40% peak aerobic capacity) aerobic exercise with different degrees of blood flow restriction (BFR) [40% estimated arterial occlusion (40 BFR) and 60% estimated arterial occlusion (60 BFR)] on variables previously hypothesized to be important for muscle adaptation. There were no meaningful changes in torque. Anterior thigh muscle thickness was increased from baseline with high intensity cycling and 40 BFR (~2 mm increase, p ≤ 0.008). A significant increase in lactate occurred in all exercise conditions but was greatest with high intensity cycling (~5.4 mmol/L increase). Muscle activation was significantly higher with high intensity cycling compared to low intensity cycling with BFR, regardless of pressure (~25% vs. ~12% MVC). Mean power frequency was not different between conditions but did increase from the first 5 minutes of exercise to the last 5 minutes (93% vs. 101%, p < 0.001). Ratings of perceived exertion (RPE) were higher with high intensity cycling but discomfort was similar between conditions. We wish to suggest that high intensity cycling produces greater muscular stress than that observed with work matched low intensity cycling in combination with BFR.

A Retrospective Evaluation of Injuries to Australian Urban Firefighters (2003 to 2012): Injury Types, Locations, and Causal Mechanisms.

Benchmark data were sought for evaluating injury trends within Australian firefighters. Work-related injury data from Australia's largest urban fire and rescue organization were analyzed (2003 to 2012), with an emphasis on classification (occurrence, mechanism, agency, nature, and location) and demographic details. Firefighters were injured on 6997 occasions (177 injuries per annum per 1000 full-time employees). The largest causal mechanism was muscular stress (74 injuries per 1000 full-time employees annually), with 62.1% of those incidents involving materials handling and slips, trips, and falls. No single mechanism could explain more than 20% of the injuries. The principal injury type involved sprains and strains. The most commonly injured sites were the knee, lower back, shoulder, and ankle. These observations provide a basis for intervention strategies that target sprains and strains associated with materials handling and slips, trips, and falls.