Explore the vast range of titles available.

This book surveys the research evidence into exercise-induced fatigue and discusses how knowledge of fatigue can be applied in sport and exercise contexts. The book examines the different \"types\" of fatigue and the difficulties of identifying which types are prevalent during different types of exercise. It introduces the fundamental science of fatigue, focusing predominantly on physiological and neuromuscular aspects, and explores key topics in detail, such as energy depletion, lactic acid, dehydration, electrolytes and minerals, and the perception of fatigue.-- From publisher's description.

Loss of mitochondrial function contributes to fatigue, exercise intolerance and muscle weakness, and is a key factor in the disability that develops with age and a wide variety of chronic disorders. Here, we describe the impact of a first-in-class cardiolipin-binding compound that is targeted to mitochondria and improves oxidative phosphorylation capacity (Elamipretide, ELAM) in a randomized, double-blind, placebo-controlled clinical trial. Non-invasive magnetic resonance and optical spectroscopy provided measures of mitochondrial capacity (ATPmax) with exercise and mitochondrial coupling (ATP supply per O2 uptake; P/O) at rest. The first dorsal interosseous (FDI) muscle was studied in 39 healthy older adult subjects (60 to 85 yrs of age; 46% female) who were enrolled based on the presence of poorly functioning mitochondria. We measured volitional fatigue resistance by force-time integral over repetitive muscle contractions. A single ELAM dose elevated mitochondrial energetic capacity in vivo relative to placebo (ΔATPmax; P = 0.055, %ΔATPmax; P = 0.045) immediately after a 2-hour infusion. No difference was found on day 7 after treatment, which is consistent with the half-life of ELAM in human blood. No significant changes were found in resting muscle mitochondrial coupling. Despite the increase in ATPmax there was no significant effect of treatment on fatigue resistance in the FDI. These results highlight that ELAM rapidly and reversibly elevates mitochondrial capacity after a single dose. This response represents the first demonstration of a pharmacological intervention that can reverse mitochondrial dysfunction in vivo immediately after treatment in aging human muscle.

Abstract Rationale Lower limb muscle dysfunction contributes to exercise intolerance in chronic obstructive pulmonary disease (COPD). We hypothesized that signaling from lower limb muscle group III/IV sensory afferents to the central motor command could be involved in premature cycling exercise termination in COPD. Objectives To evaluate the effects of spinal anesthesia, which presumably inhibited central feedback from the lower limb muscle group III/IV sensory afferents on exercise tolerance and cardiorespiratory response during constant work-rate cycling exercise in patients with COPD. Methods In a crossover and double-blind randomized design, eight patients with COPD (FEV1, 67 ± 8% predicted) completed a constant work-rate cycling exercise after sham (NaCl, interspinous L3–L4) or active (fentanyl 25 μg, intrathecal L3–L4) spinal anesthesia. Measurements and Main Results When compared with placebo, endurance time was significantly prolonged after spinal anesthesia with fentanyl (639 ± 87 s vs. 423 ± 38 s [mean ± SEM]; P = 0.01). Ventilation and respiratory rate were reduced at isotime points under the fentanyl condition, whereas ventilatory efficiency and dead space ventilation were improved. Patients exhibited less dynamic hyperinflation at isotime points with spinal anesthesia. Consequently, the rise in dyspnea was significantly flatter during the fentanyl condition than with placebo. Conclusions Spinal anesthesia enhanced cycling exercise tolerance in patients with COPD, mostly by reducing ventilatory response and dyspnea during exercise; these effects were possibly mediated through the inhibition of group III/IV lower limb sensory muscle afferents. Clinical trial registered with www.clinicaltrials.gov (NCT01522729).

Fatigue is a major cause of exercise-induced muscle damage (EIMD). Compression garments (CGs) can aid post-exercise recovery, therefore, this study explored the effects of CGs on muscular efficacy, proprioception, and recovery after exercise-induced muscle fatigue in people who exercise regularly. Twelve healthy participants who exercised regularly were enrolled in this study. Each participant completed an exercise-induced muscle fatigue test while wearing a randomly assigned lower-body CG or sports pants (SP); after at least 7 days, the participant repeated the test while wearing the other garment. The dependent variables were muscle efficacy, proprioception (displacements of center of pressure/COP, and absolute error), and fatigue recovery (muscle oxygen saturation/SmO 2 , deoxygenation and reoxygenation rate, and subjective muscle soreness). A two-way repeated measure analysis of variance was conducted to determine the effect of garment type. The results indicated that relative to SP use, CG use can promote muscle efficacy, proprioception in ML displacement of COP, and fatigue recovery. Higher deoxygenation and reoxygenation rates were observed with CG use than with SP use. For CG use, SmO 2 quickly returned to baseline value after 10 min of rest and was maintained at a high level until after 1 h of rest, whereas for SP use, SmO 2 increased with time after fatigue onset. ML displacement of COP quickly returned to baseline value after 10 min of rest and subsequently decreased until after 1 hour of rest. Relative to SP use, CG use was associated with a significantly lower ML displacement after 20 min of rest. In conclusion, proprioception and SmO 2 recovery was achieved after 10 min of rest; however, at least 24 h may be required for recovery pertaining to muscle efficacy and soreness regardless of CG or SP use.

Background Inspiratory muscle fatigue has been shown to have effects on limbs blood flow and physical performance. This study aimed to evaluate the influence of an inspiratory muscle fatigue protocol on respiratory muscle strength, vertical jump performance and muscle oxygen saturation in healthy youths. Methods A randomized and double-blinded controlled clinical trial, was conducted. Twenty-four participants aged 18–45 years, non-smokers and engaged in sports activity at least three times a week for a minimum of one year were enrolled in this investigation. Participants were randomly assigned to three groups: Inspiratory Muscle Fatigue (IMFG), Activation, and Control. Measurements of vertical jump, diaphragmatic ultrasound, muscle oxygen saturation, and maximum inspiratory pressure were taken at two stages: before the intervention (T1) and immediately after treatment (T2). Results The IMFG showed lower scores in muscle oxygen saturation and cardiorespiratory variables after undergoing the diaphragmatic fatigue intervention compared to the activation and control groups ( p  < 0.05). For the vertical jump variables, intragroup differences were found ( p  < 0.01), but no differences were shown between the three groups ( p  > 0.05). Conclusions Inspiratory muscle fatigue appears to negatively impact vertical jump performance, muscle oxygen saturation and inspiratory muscle strength in healthy youths. Trial registration ClinicalTrials.gov ID: NCT06271876. Date of registration 02/21/2024. https://clinicaltrials.gov/study/NCT06271876 .

The prevention and management of injuries in runners is a key area of research in sports medicine. Fatigue during running can lead to biomechanical imbalances and inhibition of stabilizing muscles, increasing the risk of injury. With the ankle being the most commonly injured joint in runners, rigid tape (RT) and Kinesiotape (KT) have been proposed as effective methods to improve joint stability and reduce injury risk. The objective of this study was to compare the effects of a KT and RT and no tape (control group) on lower limb balance, ankle dorsiflexion ROM, and electromyographic (EMG) activation of the pronator and supinator muscles of the ankle during a Single Leg Drop Jump (SLDJ) following a treadmill fatigue protocol. From March 1 st until April 10 th , 2024, a cross-over clinical trial with three conditions: control group, with a RT, and with KT was conducted with n = 22 well-trained runners aged 29.29 ±  10.98 years. Lower limb stability, ankle dorsiflexion mobility, SLDJ parameters, and electromyographic activation of the ankle muscles (tibialis anterior (TA), extensor digitorum longus (EDL), peroneus longus (PL), and medial gastrocnemius (MG)) during a SLDJ were analyzed Pre and Post fatigue protocol, involving a 30-minute run at 85% of the maximal aerobic speed on a treadmill. Statistical analysis was conducted using repeated-measures ANOVA with Bonferroni correction. The RT bandage decreased ankle dorsiflexion ROM compared to both KT bandage and a control group during pre fatigue treadmill protocol measurements in the lunge and Y Balance Tests (specifically in the anterior direction). Group-by-time interaction showed significant differences for the lunge test (p =  0.045), SLDJ height (p =  0.014), flight time (p =  0.019) and ground contact time (p =  0.035). With the RT condition, the runners exhibited higher peak activation of the EDL muscle compared to the KT and control group during initial landing (p =  0.028), with a lesser decay in activation during take-off (p =  0.016). The KT showed a significant increase in the activation of the PL muscle during the first contact phase of the SLDJ (p =  0.046). Concerning flight and contact time during the SLDJ, both KT and RT proved beneficial in mitigating fatigue symptoms before and after the treadmill protocol. Regarding the RT bandage’s specific effects on muscle activation, our findings indicate that the RT group exhibited higher peak activation of the EDL muscle compared to the KT and control groups during initial landing, with a lesser decay in activation during take-off. The KT showed a significant increase in the activation of the PL muscle during the first contact phase of the SLDJ. To conclude, our study highlights the potential benefits of both KT and RT in reducing fatigue symptoms during SLDJ. The study was registered with the Australian New Zealand Clinical Trials Registry (ACTRN12624000099527) on February 2 nd , 2024 ( https://anzctr.org.au/ ).

After an intense bout of exercise, foam rolling is thought to alleviate muscle fatigue and soreness (ie, delayed-onset muscle soreness [DOMS]) and improve muscular performance. Potentially, foam rolling may be an effective therapeutic modality to reduce DOMS while enhancing the recovery of muscular performance. To examine the effects of foam rolling as a recovery tool after an intense exercise protocol through assessment of pressure-pain threshold, sprint time, change-of-direction speed, power, and dynamic strength-endurance. Controlled laboratory study. University laboratory. A total of 8 healthy, physically active males (age = 22.1 ± 2.5 years, height = 177.0 ± 7.5 cm, mass = 88.4 ± 11.4 kg) participated. Participants performed 2 conditions, separated by 4 weeks, involving 10 sets of 10 repetitions of back squats at 60% of their 1-repetition maximum, followed by either no foam rolling or 20 minutes of foam rolling immediately, 24, and 48 hours postexercise. Pressure-pain threshold, sprint speed (30-m sprint time), power (broad-jump distance), change-of-direction speed (T-test), and dynamic strength-endurance. Foam rolling substantially improved quadriceps muscle tenderness by a moderate to large amount in the days after fatigue (Cohen d range, 0.59 to 0.84). Substantial effects ranged from small to large in sprint time (Cohen d range, 0.68 to 0.77), power (Cohen d range, 0.48 to 0.87), and dynamic strength-endurance (Cohen d = 0.54). Foam rolling effectively reduced DOMS and associated decrements in most dynamic performance measures.

This study is the first to determine how hypoxia affects human muscle fatigue kinetics and metabolic perturbations during intense dynamic exercise. Using randomized, single-blinded crossover designs, three trials of two-legged knee extensions were performed under hypoxic (HYP, FiO₂ 0.135) and normoxic (NOR) conditions. Trial 1 ( n  = 8): quadriceps femoris twitch force (F tw ) was measured before, during, and after 4 min intense exercise followed by exhaustive exercise. Maximal voluntary contraction (MVC) was measured pre- and post-exercise. Trial 2 ( n  = 8): muscle lactate and pH were determined before and after 4 min intense exercise. Trial 3 ( n  = 6): blood was sampled frequently from the femoral artery and vein during intense exhaustive exercise. Dynamic F tw decreased more ( P  < 0.05) in HYP from 60s of exercise and onwards. After 4 min, isometric F tw decreased more ( P  < 0.05) in HYP, whereas MVC was similar between conditions. At exhaustion, isometric F tw and MVC were similar between conditions despite HYP exercise time being 55 ± 17% of NOR ( P  < 0.01). Muscle lactate and pH in- and decreased more ( P  < 0.001), respectively, after 4 min in HYP. Exercise-induced blood metabolites disturbances were largely unaffected by hypoxia. Conclusively, moderate hypoxia accelerated muscular fatigue from 60s and onwards. Hypoxia caused higher muscle but not blood lactate and H + accumulation rates.

Recent studies with phototherapy have shown positive results in enhancement of performance and improvement of recovery when applied before exercise. However, several factors still remain unknown such as therapeutic windows, optimal treatment parameters, and effects of combination of different light sources (laser and LEDs). The aim of this study was to evaluate the effects of phototherapy with the combination of different light sources on skeletal muscle performance and post-exercise recovery, and to establish the optimal energy dose. A randomized, double-blinded, placebo-controlled trial with participation of 40 male healthy untrained volunteers was performed. A single phototherapy intervention was performed immediately after pre-exercise (baseline) maximum voluntary contraction (MVC) with a cluster of 12 diodes (4 of 905 nm lasers—0.3125 mW each, 4 of 875 nm LEDs—17.5 mW each, and 4 of 670 nm LEDs—15 mW each- manufactured by Multi Radiance Medical™) and dose of 10, 30, and 50 J or placebo in six sites of quadriceps. MVC, delayed onset muscle soreness (DOMS), and creatine kinase (CK) activity were analyzed. Assessments were performed before, 1 min, 1, 24, 48, 72, and 96 h after eccentric exercise protocol employed to induce fatigue. Phototherapy increased ( p  < 0.05) MVC was compared to placebo from immediately after to 96 h after exercise with 10 or 30 J doses (better results with 30 J dose). DOMS was significantly decreased compared to placebo ( p  < 0.05) with 30 J dose from 24 to 96 h after exercise, and with 50 J dose from immediately after to 96 h after exercise. CK activity was significantly decreased ( p  < 0.05) compared to placebo with all phototherapy doses from 1 to 96 h after exercise (except for 50 J dose at 96 h). Pre-exercise phototherapy with combination of low-level laser and LEDs, mainly with 30 J dose, significantly increases performance, decreases DOMS, and improves biochemical marker related to skeletal muscle damage.