Exploring the acute muscle fatigue response in resistance trained individuals during eccentric quasi-isometric elbow flexions-a cross-sectional comparison of repetition and sex.

Eccentric quasi-isometrics (EQIs) are a novel, low-velocity resistance exercise technique that incorporates a holding isometric contraction to positional fatigue, followed by voluntary resistance of the resulting eccentric muscle action. As females are typically more fatigue resistant than males during isometric and low-velocity dynamic muscle actions, this study explored sex-differences in the muscle fatigue response to an EQI protocol. Twenty-five (n = 12 female) participants completed 4 unilateral EQI elbow flexions. Absolute and relative surface electromyography (sEMG) amplitude (iEMG, LE peak), mean power frequency (MPF), angular impulse (aIMP), and elbow angle were compared across repetitions and between sexes using discrete values and statistical parametric/non-parametric mapping. There were significant and substantial sex and repetition differences in absolute iEMG, MPF, and aIMP, however, males and females had statistically similar absolute aIMP by repetition 4. When expressed relatively, there were no significant sex-differences. Additionally, there were significant between repetition changes in sEMG amplitude and elbow angle with an increasing number of repetitions, largely in the first-two thirds of repetition time. The current study suggests that there are absolute, but not relative sex-differences in EQI induced muscle fatigue, and the effects across repetitions occur predominately in the first two-thirds of repetition time.

A preliminary study on the effect of loaded and unloaded exercise on N-propeptide of type II collagen and serum cartilage oligomeric matrix protein activity of articular cartilage in healthy young adults.

The serum concentration of cartilage oligomeric matrix protein (sCOMP) is considered a mechanosensitive biomarker of articular cartilage turnover, and N-propeptide of type II collagen (PIIANP), a proposed biomarker of type II collagen synthesis. Few studies have investigated the anabolic and turnover response of articular cartilage in response to acute changes in body mass during exercise. Using a repeated measure cross-over design, 15 healthy adults (age 18-30 years) performed three 30 min bouts of treadmill walking exercise under three loading conditions: (1) control (no alteration to body mass); (2) loaded (12% increase in body mass using a weighted vest); and (3) unloaded (12% decrease in body mass using lower body positive pressure). Venous blood was collected before, immediately after, and 15 and 30 min after exercise to investigate cartilage turnover (sCOMP) and anabolism (PIIANP). A main time effect (p ≤ 0.05) revealed that sCOMP levels were significantly greater post-exercise (for all three body loading conditions) as compared to before exercise, 15 and 30 min post-exercise. There was a significant condition × time interaction (p ≤ 0.05) for PIIANP, indicating that in the loaded condition, PIIANP concentrations at 15 min post-exercise were 13.8% greater than immediately following exercise, and 12.9% greater than before exercise. In summary, sCOMP concentration was acutely increased with all three loading conditions. However, PIIANP increased only after exercise in the loaded condition, suggesting an acute anabolic effect on articular cartilage. NCT05925244.

A Brief Narrative Review of the Underlying Mechanisms Whereby Omega-3 Fatty Acids May Influence Skeletal Muscle: From Cell Culture to Human Interventions.

Skeletal muscle is essential for human locomotion as well as maintaining metabolic homeostasis. Age-related reduction in skeletal muscle mass, strength, and function (i.e., sarcopenia) is a result of pathophysiological processes that include inflammation, alteration of molecular signaling for muscle protein synthesis and degradation, changes in insulin sensitivity, as well as altered skeletal muscle satellite cell activity. Finding strategies to mitigate skeletal muscle loss with age is deemed paramount as the percentage of the population continues to shift towards having more older adults with sarcopenia. Recent research indicates omega-3 fatty acid supplementation can influence anabolic or catabolic pathways in skeletal muscle. Our brief review will provide a synopsis of some underlying mechanisms that may be attributed to omega-3 fatty acid supplementation's effects on skeletal muscle. We will approach this review by focusing on cell culture, animal (pre-clinical models), and human studies evaluating omega-3 fatty acid supplementation, with suggestions for future research. In older adults, omega-3 fatty acids may possess some potential to modify pathophysiological pathways associated with sarcopenia; however, it is highly likely that omega-3 fatty acids need to be combined with other anabolic interventions to effectively ameliorate sarcopenia.

Efficacy of aerobic exercise following concussion: a narrative review.

Concussion is a type of mild traumatic brain injury which results in symptoms within the physical, cognitive, emotional, and sleep domains. Historically, guidelines established by expert opinion have recommended rest during the initial stages of recovery following a concussion until symptom resolution. However, recent recommendations have shifted to advise an initial period of 24-48 h of rest immediately following concussion with the gradual introduction of light-to-moderate intensity aerobic exercise thereafter. Given the relatively recent transition in recommendations, the aim of this review is to provide an overview of the current literature on the efficacy of aerobic exercise following concussion. The current literature is limited to studies assessing the impact of standardized aerobic exercise following concussion. Upon review, literature suggests participating in aerobic exercise below the point of symptom exacerbation is safe in both the acute and chronic post-concussion symptom stages of recovery and does not delay time to medical clearance. Future large-scale randomized controlled trials assessing the impact of aerobic exercise and differences between males and females would help support the current evidence suggesting aerobic exercise could improve time to recovery following concussion and identify any sex differences in response. As well, future studies with the purpose of identifying optimal aerobic exercise volume and intensity in the treatment of concussion could improve the specificity of the current guidelines.

Effects of resistance training and nigella sativa on type 2 diabetes: implications for metabolic markers, low-grade inflammation and liver enzyme production.

CONTEXT: Proper nutrition and exercise are effective strategies to improve overall metabolic health in diabetic patients. OBJECTIVE: This study evaluated the effects of Nigella sativa (NS) supplementation during resistance training (RT) on some biochemical variables in type 2 diabetes patients. METHODS: Forty patients were assigned to groups: RT + NS (RN), NS, RT + placebo (RP), and control (CO). RT was performed and NS was consumed for 8 weeks. Blood samples were collected at rest immediately before and after the 8 week intervention. RESULTS: RT or NS by themselves reduced HOMA-IR, insulin, glucose, TG, TC, LDL, ESR, CRP, AST, ALT and ALP, and increased HDL and HOMA-S. The combination of RT and NS, rather than each intervention alone, had significant effects on reduction of HOMA-IR, insulin, ESR and CRP as well as increases in HDL, HOMA-ß/S. CONCLUSION: RT combined with NS is sometimes a better strategy compared to single interventions for improving diabetes related biomarkers in type 2 diabetic patients.

Omega-3 Fatty Acids for the Management of Osteoarthritis: A Narrative Review.

Osteoarthritis (OA) is a disease which results in degeneration of cartilage within joints and affects approximately 13.6% of adults over 20 years of age in Canada and the United States of America. OA is characterized by a state of low-grade inflammation which leads to a greater state of cellular catabolism disrupting the homeostasis of cartilage synthesis and degradation. Omega-3 polyunsaturated fatty acids (PUFAs) have been postulated as a potential therapeutic treatment option for individuals with OA. Omega-3 PUFAs are recognized for their anti-inflammatory properties, which could be beneficial in the context of OA to moderate pro-inflammatory markers and cartilage loss. The purpose of this narrative review is to outline recent pre-clinical and clinical evidence for the use of omega-3 in the management of OA.

Effects of Omega-3 Supplementation Alone and Combined with Resistance Exercise on Skeletal Muscle in Older Adults: A Systematic Review and Meta-Analysis.

Sarcopenia negatively affects skeletal muscle mass and function in older adults. Omega-3 (ω-3) fatty acid supplementation, with or without resistance exercise training (RET), is suggested to play a role as a therapeutic component to prevent or treat the negative effects of sarcopenia. A systematic review and meta-analysis were conducted on the impact of ω-3 fatty acid supplementation with or without RET on measures of muscle mass and function in older adults (≥55 y). The data sources included SPORTDiscus, PubMed, and Medline. All the study types involving ω-3 fatty acid supplementation on measures of muscle mass and function in older adults (without disease) were included. The mean differences (MDs) or standardized mean differences (SMDs) with 95% confidence intervals were calculated and pooled effects assessed. Sixteen studies (1660 females, 778 males) met our inclusion criteria and were included in the meta-analysis. ω-3 fatty acid supplementation did not impact lean tissue mass (SMD 0.09 [-0.10, 0.28]). Benefits were observed for lower body strength (SMD 0.54 [0.33, 0.75]), timed-up-and-go (MD 0.29 [0.23, 0.35]s), and 30-s sit-to-stand performance (MD 1.93 [1.59, 2.26] repetitions) but not walking performance (SMD -0.01 [-0.10, 0.07]) or upper body strength (SMD 0.05 [-0.04, 0.13]). Supplementing with ω-3 fatty acids may improve the lower-body strength and functionality in older adults.

Effects of Creatine Supplementation on Brain Function and Health.

While the vast majority of research involving creatine supplementation has focused on skeletal muscle, there is a small body of accumulating research that has focused on creatine and the brain. Preliminary studies indicate that creatine supplementation (and guanidinoacetic acid; GAA) has the ability to increase brain creatine content in humans. Furthermore, creatine has shown some promise for attenuating symptoms of concussion, mild traumatic brain injury and depression but its effect on neurodegenerative diseases appears to be lacking. The purpose of this narrative review is to summarize the current body of research pertaining to creatine supplementation on total creatine and phophorylcreatine (PCr) content, explore GAA as an alternative or adjunct to creatine supplementation on brain creatine uptake, assess the impact of creatine on cognition with a focus on sleep deprivation, discuss the effects of creatine supplementation on a variety of neurological and mental health conditions, and outline recent advances on creatine supplementation as a neuroprotective supplement following traumatic brain injury or concussion.

Anti-Inflammatory and Anti-Catabolic Effects of Creatine Supplementation: A Brief Review.

It is well established that creatine supplementation, primarily when combined with resistance training, significantly increases measures of muscle mass and performance (primarily strength). Emerging research also indicates that creatine supplementation may have favorable effects on measures of bone biology. These anabolic adaptations may be related to creatine influencing cellular hydration status, high-energy phosphate metabolism, growth factors, muscle protein kinetics, and the bone remodeling process. Accumulating research also suggests that creatine supplementation has anti-inflammatory and anti-catabolic properties, which may help create a favorable environment for muscle and bone accretion and recovery from exercise. Creatine supplementation has the ability to decrease markers of inflammation and possibly attenuate cancerous tumor growth progression. From a musculoskeletal perspective, there is some evidence to show that creatine supplementation reduces measures of muscle protein catabolism (primarily in males) and bone resorption when combined with resistance training. The purpose of this brief review is to summarize the current body of literature examining the potential anti-inflammatory and anti-catabolic effects of creatine supplementation across various research populations.

Potential Importance of Immune System Response to Exercise on Aging Muscle and Bone.

PURPOSE OF REVIEW: The age-related loss of skeletal muscle and bone tissue decreases functionality and increases the risk for falls and injuries. One contributing factor of muscle and bone loss over time is chronic low-grade inflammation. Exercise training is an effective countermeasure for decreasing the loss of muscle and bone tissue, possibly by enhancing immune system response. Herein, we discuss key interactions between the immune system, muscle, and bone in relation to exercise perturbations, and we identify that there is substantial "cross-talk" between muscle and bone and the immune system in response to exercise. RECENT FINDINGS: Recent advances in our understanding of the "cross-talk" between muscle and bone and the immune system indicate that exercise is likely to mediate many of the beneficial effects on muscle and bone via their interactions with the immune system. The age-related loss of muscle and bone tissue may be partially explained by an impaired immune system via chronic low-grade inflammation. Exercise training has a beneficial effect on immune system function and aging muscle and bone. Theoretically, the "cross-talk" between the immune system, muscle, and bone in response to exercise enhances aging musculoskeletal health.

Skin Cooling on Breath-Hold Duration and Predicted Emergency Air Supply Duration During Immersion.

PURPOSE: This study was intended to determine the effect of skin cooling on breath-hold duration and predicted emergency air supply duration during immersion.METHODS: While wearing a helicopter transport suit with a dive mask, 12 subjects (29 ± 10 yr, 78 ± 14 kg, 177 ± 7 cm, 2 women) were studied in 8 and 20°C water. Subjects performed a maximum breath-hold, then breathed for 90 s (through a mouthpiece connected to room air) in five skin-exposure conditions. The first trial was out of water for Control (suit zipped, hood on, mask off). Four submersion conditions included exposure of the: Partial Face (hood and mask on); Face (hood on, mask off); Head (hood and mask off); and Whole Body (suit unzipped, hood and mask off).RESULTS: Decreasing temperature and increasing skin exposure reduced breath-hold time (to as low as 10 ± 4 s), generally increased minute ventilation (up to 40 ± 15 L · min-1), and decreased predicted endurance time (PET) of a 55-L helicopter underwater emergency breathing apparatus. In 8°C water, PET decreased from 2 min 39 s (Partial Face) to 1 min 11 s (Whole Body).CONCLUSION: The most significant factor increasing breath-hold and predicted survival time was zipping up the suit. Face masks and suit hoods increased thermal comfort. Therefore, wearing the suits zipped with hoods on and, if possible, donning the dive mask prior to crashing, may increase survivability. The results have important applications for the education and preparation of helicopter occupants. Thermal protective suits and dive masks should be provided.Madu VC, Carnahan H, Brown R, Ennis K-A, Tymko KS, Hurrie DMG, McDonald GK, Cornish SM, Giesbrecht GG. Skin cooling on breath-hold duration and predicted emergency air supply duration during immersion. Aerosp Med Hum Perform. 2020; 91(7):578-585.

Effects of Training With Free Weights Versus Machines on Muscle Mass, Strength, Free Testosterone, and Free Cortisol Levels.

Schwanbeck, SR, Cornish, SM, Barss, T, and Chilibeck, PD. Effects of training with free weights versus machines on muscle mass, strength, free testosterone, and free cortisol levels. J Strength Cond Res 34(7): 1851-1859, 2020-Free weights offer a more unstable training environment, which enhances muscle recruitment, whereas some machines have the advantage of using a "cam" pulley system that better matches strength curves. We compared the effect of training with free weights vs. machines on muscle mass, strength, free testosterone, and free cortisol concentrations. Forty-six subjects (26 women; 22 ± 3 years) were randomized to train using free weights or machines for 8 weeks (with each muscle group trained 2-3/weeks, 3-4 sets of 4-10 repetitions). Muscle thickness and strength were measured at 0 and 8 weeks. Salivary hormone concentrations were assessed before and at the end of workouts at the beginning, midway (4 weeks), and end (8 weeks) of the training intervention. Biceps and quadriceps muscle thickness increased (p < 0.01) with no difference between groups. There was a group × time interaction for machine bench press strength (p = 0.05) with the machine group increasing more than the free-weight group (13.9 vs. 8.6%). Free-weight bench press and squat, and Smith machine squat strength increased in both groups (11-19%; p < 0.01) with no difference between groups. Men in the free-weight group had a greater increase in free testosterone from before to after acute training sessions than men in the machine group and all women (p < 0.01); however, there was no differences between groups in free cortisol response to acute resistance exercise. Training sessions with free weights induced greater increases in free testosterone in men; however, training with free weights or machines resulted in similar increases in muscle mass and strength.

A focused review of myokines as a potential contributor to muscle hypertrophy from resistance-based exercise.

PURPOSE: Resistance exercise induces muscle growth and is an important treatment for age-related losses in muscle mass and strength. Myokines are hypothesized as a signal conveying physiological information to skeletal muscle, possibly to "fine-tune" other regulatory pathways. While myokines are released from skeletal muscle following contraction, their role in increasing muscle mass and strength in response to resistance exercise or training is not established. Recent research identified both local and systemic release of myokines after an acute bout of resistance exercise. However, it is not known whether myokines with putative anabolic function are mechanistically involved in producing muscle hypertrophy after resistance exercise. Further, nitric oxide (NO), an important mediator of muscle stem cell activation, upregulates the expression of certain myokine genes in skeletal muscle. METHOD: In the systemic context of complex hypertrophic signaling, this review: (1) summarizes literature on several well-recognized, representative myokines with anabolic potential; (2) explores the potential mechanistic role of myokines in skeletal muscle hypertrophy; and (3) identifies future research required to advance our understanding of myokine anabolism specifically in skeletal muscle. RESULT: This review establishes a link between myokines and NO production, and emphasizes the importance of considering systemic release of potential anabolic myokines during resistance exercise as complementary to other signals that promote hypertrophy. CONCLUSION: Investigating adaptations to resistance exercise in aging opens a novel avenue of interdisciplinary research into myokines and NO metabolites during resistance exercise, with the longer-term goal to improve muscle health in daily living, aging, and rehabilitation.

Variables Influencing the Effectiveness of Creatine Supplementation as a Therapeutic Intervention for Sarcopenia.

Sarcopenia is an age-related muscle condition characterized by a reduction in muscle quantity, force generating capacity and physical performance. Sarcopenia occurs in 8-13% of adults ≥ 60 years of age and can lead to disability, frailty, and various other diseases. Over the past few decades, several leading research groups have focused their efforts on developing strategies and recommendations for attenuating sarcopenia. One potential nutritional intervention for sarcopenia is creatine supplementation. However, research is inconsistent regarding the effectiveness of creatine on aging muscle. The purpose of this perspective paper is to: (1) propose possible reasons for the inconsistent responsiveness to creatine in aging adults, (2) discuss the potential mechanistic actions of creatine on muscle biology, (3) determine whether the timing of creatine supplementation influences aging muscle, (4) evaluate the evidence investigating the effects of creatine with other compounds (protein, conjugated linoleic acid) in aging adults, and (5) provide insight regarding the safety of creatine for aging adults.

Effectiveness of Creatine Supplementation on Aging Muscle and Bone: Focus on Falls Prevention and Inflammation.

Sarcopenia, defined as the age-related decrease in muscle mass, strength and physical performance, is associated with reduced bone mass and elevated low-grade inflammation. From a healthy aging perspective, interventions which overcome sarcopenia are clinically relevant. Accumulating evidence suggests that exogenous creatine supplementation has the potential to increase aging muscle mass, muscle performance, and decrease the risk of falls and possibly attenuate inflammation and loss of bone mineral. Therefore, the purpose of this review is to: (1) summarize the effects of creatine supplementation, with and without resistance training, in aging adults and discuss possible mechanisms of action, (2) examine the effects of creatine on bone biology and risk of falls, (3) evaluate the potential anti-inflammatory effects of creatine and (4) determine the safety of creatine supplementation in aging adults.

Omega-3 supplementation with resistance training does not improve body composition or lower biomarkers of inflammation more so than resistance training alone in older men.

The purpose of this study was to evaluate the effectiveness of 3.0 g/d of omega-3 fatty acid (eicosapentaenoic acid and docosahexaenoic acid) supplementation combined with progressive resistance training to improve body composition and lower inflammatory cytokines in older men when compared to placebo and resistance training. We hypothesized that completing a 12-week omega-3 supplementation period along with whole body resistance exercise (3 times/wk) would result in a significantly greater improvement in lean tissue mass as well as a significant decrease in interleukin-6 and tumor necrosis factor-α when compared to placebo. A total of 23 older men (≥65 years old) were randomized to an omega-3 supplementation group (n = 11) or placebo group (n = 12), and all the participants completed the same whole body progressive resistance training program. Baseline and 12-week data collection included body composition, muscle strength, functional ability, and inflammatory cytokines. Results indicated a significant main effect for time (all P < .05) for percent body fat (-2.5%), lean tissue mass (+1.1%), lumbar bone mineral density (+1.1%), hip bone mineral content (+1.1%), chest press strength (+31%), leg press strength (+37%), timed-up-and-go (-6.6%), and 6-minute walk distance (+4.5%) from baseline to post 12 weeks. No significant effects were noted for the 2 inflammatory cytokines measured (P > .05). We conclude that progressive resistance training exercise is an excellent method to enhance parameters of body composition, skeletal muscle strength, and functional ability in older men, whereas omega-3 supplementation did nothing to enhance these parameters or influence inflammatory biomarkers.

The systemic myokine response of decorin, interleukin-6 (IL-6) and interleukin-15 (IL-15) to an acute bout of blood flow restricted exercise.

PURPOSE: Blood flow restricted resistance exercise (BFR-RE) is an emerging hypertrophy training modality. A complete profile of its mechanisms of action has yet to be elucidated. Cytokines are universal intercellular messengers. Recent research has implicated certain cytokines (termed "myokines") in skeletal muscle hypertrophy pathways; however, little research has been conducted on the systemic myokine response to BFR-RE as potential hypertrophic biomarkers. Therefore, this project was conducted to determine any differences in the systemic myokine response between BFR-RE and control conditions. METHODS: The appearance of systemic myokines interleukin-6 (IL-6), interleukin-15 (IL-15), and decorin were measured following acute bouts of low-load resistance exercise, BFR-RE, and high-load resistance exercise in physically active young males to determine if BFR-RE modifies the exercise-induced systemic myokine response. RESULTS: No measurable levels of IL-6 were observed during the project. No significant effects were observed for IL-15. A significant time (11.91% increase pre to post exercise; p < 0.05) but no condition or condition by time effect was observed for decorin. CONCLUSION: These findings suggest that BFR-RE does not modify the systemic myokine appearance of IL-6, IL-15, or decorin when compared to control conditions.

No effect of creatine monohydrate supplementation on inflammatory and cartilage degradation biomarkers in individuals with knee osteoarthritis.

The study purpose was to evaluate the effectiveness of creatine monohydrate supplementation (20 grams/day for 1 week and then 5 grams/day for 11 weeks) on inflammation (C-reactive protein, interleukin-1ß, interleukin-6, s100 A8/A9, and tumor necrosis factor-α) and cartilage degradation (serum cartilage oligomeric matrix protein) in patients with knee osteoarthritis. We hypothesized that supplementing with creatine monohydrate for 12 weeks would lower biomarkers of inflammation and cartilage degradation in patients with knee osteoarthritis when compared to placebo. A total of 18 patients with mild to moderate knee osteoarthritis were recruited and randomized in a double blind fashion to either a creatine supplementation group (N = 9) or a placebo (N = 9). At baseline and after 12 weeks of supplementation patients had inflammatory and cartilage degradation biomarkers measured in the systemic blood. Further, patients completed the Knee injury and Osteoarthritis Outcome (KOOS) questionnaire as well as had their isometric thigh strength evaluated using an isokinetic dynamometer at both time points. Results indicated that there was no difference between the creatine and placebo groups at 12 week follow up in the inflammatory biomarkers measured nor was there any difference between the groups for cartilage degradation (all P>.05). No statistical differences were noted for the KOOS questionnaire subscales or total score (all P>.05). Muscle strength testing indicated a main effect of time for both groups where isometric thigh strength at 0° of knee flexion was lowered significantly (P=.047). No other significant differences were found in the strength data. We conclude that 12 weeks of supplementation with creatine monohydrate does not affect inflammatory biomarkers, cartilage degradation, KOOS scores, or muscle strength in patients with mild to moderate knee osteoarthritis.