Skeletal muscle oxidative adaptations following localized heat therapy

Thermal Modalities Including Hot Baths and Cold Plunges Play a Unique Role in Injury Prevention and Recovery

There are several different modalities for injury prevention to consider in order to help our patients' reach their ultimate goals. The purpose of this review is to analyze the use of hot and cold therapies to prevent injury. Thermotherapy has been used in clinical rehabilitation settings to treat health conditions. The therapeutic use of cold, known as cryotherapy, is historically the most popular treatment for acute musculoskeletal injury or fatigue. Cold therapy was seen to decrease delayed-onset muscle soreness and help resolve global or generalized muscle injury or fatigue. In sum, both cold and hot therapy play similar but unique roles in injury prevention and recovery. The key to effective use of either depends on understanding the nature of the injury and mastering the appropriate timing of therapeutic application. By leveraging the unique mechanisms of each modality, athletes can optimize their recovery process and reduce the risk of future injury.

Level of Evidence

Level V, expert opinion.

Effects of thermal interventions on skeletal muscle adaptations and regeneration: perspectives on epigenetics: a narrative review

Recovery methods, such as thermal interventions, have been developed to promote optimal recovery and maximize long-term training adaptations. However, the beneficial effects of these recovery strategies remain a source of controversy. This narrative review aims to provide a detailed understanding of how cold and heat interventions impact long-term training adaptations. Emphasis is placed on skeletal muscle adaptations, particularly the involvement of signaling pathways regulating protein turnover, ribosome and mitochondrial biogenesis, as well as the critical role of satellite cells in promoting myofiber regeneration following atrophy. The current literature suggests that cold interventions can blunt molecular adaptations (e.g., protein synthesis and satellite cell activation) and oxi-inflammatory responses after resistance exercise, resulting in diminished exercise-induced hypertrophy and lower gains in isometric strength during training protocols. Conversely, heat interventions appear promising for mitigating skeletal muscle degradation during immobilization and atrophy. Indeed, heat treatments (e.g., passive interventions such as sauna-bathing or diathermy) can enhance protein turnover and improve the maintenance of muscle mass in atrophic conditions, although their effects on uninjured skeletal muscles in both humans and rodents remain controversial. Nonetheless, heat treatment may serve as an important tool for attenuating atrophy and preserving mitochondrial function in immobilized or injured athletes. Finally, the potential interplay between exercise, thermal interventions and epigenetics is discussed. Future studies must be encouraged to clarify how repeated thermal interventions (heat and cold) affect long-term exercise training adaptations and to determine the optimal modalities (i.e., method of application, temperature, duration, relative humidity, and timing).

Impact of foam rolling with and without vibration on muscle oxidative metabolism and microvascular reactivity

Background and Purpose

There is a growing interest in use vibration foam rolling as a warm up and recovery tool. However, whether vibration foam rolling offers additional benefits to traditional foam rolling is unclear. The current study aims to compare the effects of acute foam rolling, with and without vibration, on skeletal muscle metabolism and microvascular reactivity.

Methods

Fifteen physically active young males were tested on two different days, with gastrocnemius muscle microvascular function assessed using near-infrared spectroscopy coupled with the post-occlusive reactive hyperemia technique, before and after foam rolling, performed with or without vibration. The slope of tissue saturation index (TSI) decrease during occlusion between 120 s to 150 s (TSI occlusion slope) was assessed for muscle metabolic rate. Three commonly used microvascular function indexes, including the first10s TSI slope after occlusion (TSI10), time for TSI to reach half of peak magnitude (TSI1/2), and TSI peak reactive hyperemia, were also assessed.

Results

None of the measured indexes showed significance for interaction or method (all p > 0.05). However, there was a main effect for time for TSI occlusion slope, TSI1/2, and TSI peak reactive hyperemia (p = 0.005, 0.034 and 0.046, respectively). No main effect for time for TSI10 was detected (p = 0.963).

Conclusions

The application of foam rolling can decrease muscle metabolism, and may improve some aspects of muscle microvascular function. However, vibration foam rolling does not seem to offer any additional benefits compared to traditional foam rolling alone.

Sex-specific microvascular and hemodynamic responses to passive limb heating in young adults

OBJECTIVE

We examined sex-specific microvascular reactivity and hemodynamic responses under conditions of augmented resting blood flow induced by passive heating compared to normal blood flow.

METHODS

Thirty-eight adults (19 females) completed a vascular occlusion test (VOT) on two occasions preceded by rest with or without passive heating in a randomized, counterbalanced order. Skeletal muscle tissue oxygenation (StO2, %) was assessed with near-infrared spectroscopy (NIRS), and the rate of desaturation and resaturation as well as maximal StO2 (StO2max) and prolonged hypersaturation (area under the curve, StO2AUC) were quantified. Before the VOT, brachial artery blood flow (BABF), vascular conductance, and relative BABF (BABF normalized to forearm lean mass) were determined. Sex × condition ANOVAs were used. A p-value ≤.05 was considered statistically significant.

RESULTS

Twenty minutes of heating increased BABF compared to the control (102.9 ± 28.3 vs. 36.0 ± 20.9 mL min-1; p < .01). Males demonstrated greater BABF than females (91.9 ± 34.0 vs. 47.0 ± 19.1 mL min-1; p < .01). There was no sex difference in normalized BABF. There were no significant interactions for NIRS-VOT outcomes, but heat did increase the rate of desaturation (-0.140 ± 0.02 vs. -0.119 ± 0.03% s-1; p < .01), whereas regardless of condition, males exhibited greater rates of resaturation and StO2max than females.

CONCLUSIONS

These results suggest that blood flow is not the primary factor causing sex differences in NIRS-VOT outcomes.

Evaluation of Tibial Hemodynamic Response to Glucose Tolerance Test in Young Healthy Males and Females

The relationship between glucose metabolism and bone health remains underexplored despite its clinical relevance. This study utilized the oral glucose tolerance test (OGTT) and near-infrared spectroscopy (NIRS) to probe gender-specific disparities in tibial hemodynamic responses among young healthy adults. Twenty-eight healthy participants (14 males) aged 18-28 years old were recruited for this study. After ingesting a 75 g glucose solution, tibial hemodynamic responses were captured using NIRS in combination with a 5 min ischemic reperfusion technique, both before and at 30 min intervals for two hours post-glucose ingestion. Parameters measured included oxidative metabolic rate (via tissue saturation index [TSI]), immediate recovery slope after occlusion release (TSI10), and total recovery magnitude (ΔTSI). Post-glucose ingestion, both genders demonstrated a surge in blood glucose concentrations at every time point compared to baseline (p < 0.001, 0.002, 0.009, and 0.039 for males; p < 0.001, < 0.001, = 0.002, and 0.017 for females). Baseline tibial metabolic rate, TSI10, and ΔTSI did not significantly differ between males and females (p = 0.734, 0.839, and 0.164, respectively), with no discernible temporal effects in any hemodynamic parameters within each gender (p = 0.864, 0.308, and 0.399, respectively, for males; p = 0.973, 0.453, and 0.137, respectively, for females). We found comparable tibial hemodynamic responses to OGTT between genders. This study demonstrated the utility of NIRS in evaluating tibial hemodynamic responses to glucose ingestion through OGTT, enriching our understanding of the body's metabolic responses to glucose intake.