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Cooling Down to Level Up: Does Interset Palm or Sole Cooling Enhance Resistance Training Performance?
Abstract
An emerging body of research has explored the potential ergogenic effects of noninvasive interset recovery strategies involving the application of cold substances to the extremities distal to exercising muscles (e.g., palms of the hands or the soles of the feet). It was suggested that such strategies may acutely enhance resistance training (RT) performance by augmenting excitation and motor unit recruitment of the working muscles through enhanced stimulation of the central nervous system, resulting in greater force production and the ability to perform more repetitions to fatigue. Moreover, peripheral stimuli such as distal cooling may acutely reduce the sensation of distress during RT, allowing individuals to tolerate more exercise and achieve higher training volumes. Although there is some evidence that interset distal cooling confers an ergogenic benefit during RT, certain methodological considerations, a paucity of longitudinal research, and contrasting findings call into question its effectiveness. Thus, the purpose of this review is to assess the current evidence regarding the effects of interset palm and sole cooling on RT performance outcomes.
... Modern ergogenic methods are focused on prolonging the capacity for high training volume to augment skeletal muscle hypertrophy. In this context, intermittent cooling has gained prominence over the last decade (Burke et al., 2024). This technique typically involves the application of external cooling devices to palms (PC) or soles (SC) during the rest periods between sets of resistance exercise (Burke et al., 2024). ...
... In this context, intermittent cooling has gained prominence over the last decade (Burke et al., 2024). This technique typically involves the application of external cooling devices to palms (PC) or soles (SC) during the rest periods between sets of resistance exercise (Burke et al., 2024). The rationale for using intermittent cooling in resistance training is multifaceted. ...
... Even in resistance-trained populations, results have been inconsistent. (Esteves et al., 2021) A recently published review has attempted to synthesize this body of work, highlighting the considerable uncertainty surrounding intermittent cooling (Burke et al., 2024). While the study offers a broad overview of current research, the field still lacks a comprehensive meta-analysis that quantitatively evaluates the magnitude of intermittent cooling's effects on resistance training volume. ...
Intermittent palm (PC) and sole cooling (SC) are emerging techniques with potential ergogenic effects under high-intensity and fatiguing exercise conditions. However, evidence regarding their efficacy remains inconclusive. This systematic review and meta-analysis aims to summarize the acute effects of intermittent PC and SC applied during inter-set rest periods on resistance training volume and rate of perceived exertion (RPE) in healthy individuals. A systematic literature search in the electronic databases Cochrane, PubMed, Scopus, SPORTDiscus, and Web of Science identified 10 studies (n = 182 participants, 40 female, mean age range: 19 – 26 years). Effect sizes (Cohen’s dz) were calculated for each study and corrected for small sample bias (Hedges g). Meta-analyses were conducted using a random-effects model and an inverse variance method. PC and SC were applied for 1–3 min (2.3 ± 0.7 min) with temperatures ranging from 10–15 °C (12.0 ± 2.2 °C). Based on the current literature, no significant effect of PC or SC on resistance training volume was observed (n = 12, g = 0.22, 95%CI [-0.27, 0.72], p = 0.345), with high heterogeneity values indicating considerable variability among studies. Furthermore, no significant effect of PC or SC on RPE was found (n = 9, g = 0.10, 95%CI [-0.15, 0.32], p = 0.389). Based on current evidence, intermittent PC and SC cannot be generally recommended for resistance training volume enhancement.
... For instance, [22] demonstrated that higher muscle temperatures are associated with improved sprint performance, a finding corroborated by subsequent research involving isokinetic cycling [4]. Crucially, it is still debated, whether or not resistance exercise reliably produces a notable increase in core temperature, specifically in relation to the employed training parameters, i.e., the load, number of sets, and number of repetitions [23]. In Protocol 3, TT measurements, considered to be reliable indicators of core body temperature [24,25], did not reveal differences across six sets of leg extensions, nor between SC and NC conditions, indicating that intermittent cooling did not significantly affect core temperature regulation during leg extensions. ...
Intermittent palm (PC) and sole cooling (SC) are proposed ergogenic methods for enhancing exercise performance during high-intensity and fatiguing conditions. However, findings in the literature regarding its positive effect remain inconclusive. This study aimed at investigating the effects of intermittent PC and SC compared to no cooling (NC) on acute training volume during resistance exercise, particularly focusing on the total number of repetitions (TR) performed. Three separate randomized crossover protocols, incorporating commonly practiced resistance exercises (Protocol 1: pullups; Protocol 2: pushups; Protocol 3: leg extensions), were conducted, enrolling healthy, physically active adults (overall sample: n = 41 (12 female), age: 23.9 ± 4.0 years (mean ± SD), height: 174.4 ± 9.5 cm, body mass: 69.3 ± 12.4 kg). During Protocol 3, tympanic temperature (TT), rate of perceived exertion (RPE), and electromyography (EMG) of quadriceps muscles were additionally assessed for SC. PC resulted in less TR compared to NC in Protocol 1 (p < 0.001). Protocol 2 and 3 did not reveal significant ergogenic benefits of PC or SC compared to NC (p > 0.05). Furthermore, SC had no effect on TT, RPE, or EMG amplitudes (all p > 0.05). The inconsistent findings suggest that intermittent PC and SC might have limited effectiveness in enhancing training volume during resistance exercise in physically active adults. Future research should examine various resistance training protocols under controlled conditions, and incorporate comprehensive physiological measurements to elucidate the potential benefits and mechanisms of intermittent cooling in resistance exercise contexts.
McMahon, G, Kennedy, R, and Burden, A. No effect of interset palm cooling on acute bench press performance, electromyography amplitude or spectral frequencies in resistance-trained men. J Strength Cond Res 37(3): 555-563, 2023-Previous research has suggested that cooling distal to the working agonist muscles during the interset rest periods of high-intensity resistance exercise may facilitate improved performance through increased agonist activation. However, these studies have used inappropriate electromyography (EMG) normalization techniques. Therefore, the aim of this study was to compare 2 palm-cooling conditions with a thermoneutral condition during high-intensity resistance exercise and subsequent effects on exercise performance, EMG amplitude, and spectral frequencies using appropriate normalization methodologies. Eleven healthy, resistance-trained, young men (20-36 years old) performed 4 sets of bench press exercise to exhaustion at 80% 1RM each separated by 3 minutes of passive recovery. Palm-cooling (10° C [TEN] or 15° C [FTN]) or thermoneutral (28° C [CON]) conditions were applied for 60 seconds during the recovery interval of each set in a randomized, double-blind fashion, with 4 days of recovery between experimental conditions. Palm temperature was significantly lower (p < 0.05) in the TEN and FTN conditions compared with CON. Number of repetitions and mean power in the bench press declined significantly after each set in all conditions (p < 0.05). There were no significant differences (p > 0.05) in any bench press performance or EMG-related variables between any of the conditions. Palm cooling at either 10 or 15° C had no effects on bench press performance compared with a thermoneutral condition, with no observable effects on neuromuscular responses during exercise. Therefore, cooling is not currently recommended as an ergogenic strategy to enhance acute bench press performance during high-intensity resistance training.
Inter-set peripheral cooling can improve high-intensity resistance exercise performance. However, whether foot cooling (FC) would increase 1 repetition maximum (RM) lower-limb strength is unclear. This study investigated the effect of intermittent FC on 1 RM leg press strength. Ten recreational male lifters performed three attempts of 1 RM leg press with FC or non-cooling (NC) in a repeated-measures crossover design separated by 5 days. FC was applied by foot immersion in 10 °C water for 2.5 min before each attempt. During the 1 RM test, various physiological measures were recorded. The results showed that FC elicited higher 1 RM leg press strength (Δ [95% CI]; Cohen's d effect size [ES]; 13.6 [7.6–19.5] kg; ES = 1.631) and electromyography values in vastus lateralis (57.7 [ 8.1–107.4] μV; ES = 0.831) and gastrocnemius (15.1 [-3.1–33.2] μV; ES = 0.593) than in NC. Higher arousal levels (felt arousal scale) were found in FC (0.6 [0.1–1.2]; ES = 0.457) than in NC. In conclusion, the preliminary findings, although limited, suggest intermittent FC has a potential ergogenic role for recreational athletes to enhance maximal lower-limb strength and may partly benefit strength-based competition events.
Creatine supplementation in conjunction with resistance training (RT) augments gains in lean tissue mass and strength in aging adults; however, there is a large amount of heterogeneity between individual studies that may be related to creatine ingestion strategies. Therefore, the purpose of this review was to (1) perform updated meta-analyses comparing creatine vs. placebo (independent of dosage and frequency of ingestion) during a resistance training program on measures of lean tissue mass and strength, (2) perform meta-analyses examining the effects of different creatine dosing strategies (lower: ≤5 g/day and higher: >5 g/day), with and without a creatine-loading phase (≥20 g/day for 5–7 days), and (3) perform meta-analyses determining whether creatine supplementation only on resistance training days influences measures of lean tissue mass and strength. Overall, creatine (independent of dosing strategy) augments lean tissue mass and strength increase from RT vs. placebo. Subanalyses showed that creatine-loading followed by lower-dose creatine (≤5 g/day) increased chest press strength vs. placebo. Higher-dose creatine (>5 g/day), with and without a creatine-loading phase, produced significant gains in leg press strength vs. placebo. However, when studies involving a creatine-loading phase were excluded from the analyses, creatine had no greater effect on chest press or leg press strength vs. placebo. Finally, creatine supplementation only on resistance training days significantly increased measures of lean tissue mass and strength vs. placebo.
Purpose:
The authors investigated the effect of foot cooling (FC) between sets in a leg press pyramid workout with resistance-trained participants.
Methods:
A total of 12 resistance-trained men (age = 21.8 [0.6] y; training experience = 1.7 [1] y) performed a pyramid workout, including 4 sets of 85% to 90% 1-repetition maximum leg press exercise to exhaustion with interset FC or noncooling in a repeated-measures crossover design separated by 5 days. The authors immersed the participants' feet in 10°C water for 2.5 minutes between sets.
Results:
Two-way repeated-measures analysis of variance revealed that FC elicited significantly higher repetitions and electromyography (EMG) values of the vastus lateralis (simple main effect of condition) than did noncooling (P < .05) in the second (repetitions: 11 [3.5] vs 7.75 [3.2]; EMG: 63.4% [19.4%] vs 54.5% [18.4%]), third (repetitions: 8.9 [3.2] vs 6.4 [2.1]; EMG: 71.5% [17.4%] vs 60.6% [19.4%]), and fourth (repetitions: 7.5 [2.7] vs 5.1 [2.2]; EMG: 75.2% [19.6%] vs 59.3% [23.5%]) sets. The authors also detected a simple main effect of set in the FC and noncooling conditions on repetitions (P < .05) and in the FC condition on the vastus lateralis EMG values. Although the authors observed no time × trial interactions for the rating of perceived exertion, the authors observed main effects on the sets (7.7-9.6 vs 7.9-9.3, P < .05).
Conclusions:
Interset FC provides an ergogenic effect on a leg press pyramid workout and may offset fatigue, as indicated by higher repetitions and EMG response, without increasing perceived exertion.
Anabolic-androgenic steroids (AASs) are a large group of molecules including endogenously produced androgens, such as testosterone, as well as synthetically manufactured derivatives. AAS use is widespread due to their ability to improve muscle growth for aesthetic purposes and athletes’ performance, minimizing androgenic effects. AAS use is very popular and 1–3% of US inhabitants have been estimated to be AAS users. However, AASs have side effects, involving all organs, tissues and body functions, especially long-term toxicity involving the cardiovascular system and the reproductive system, thereby, their abuse is considered a public health issue. The aim of the proposed review is to highlight the most recent evidence regarding the mechanisms of action of AASs and their unwanted effects on organs and lifestyle, as well as suggesting that AAS misuse and abuse lead to adverse effects in all body tissues and organs. Oxidative stress, apoptosis, and protein synthesis alteration are common mechanisms involved in AAS-related damage in the whole body. The cardiovascular system and the reproductive system are the most frequently involved apparatuses. Epidemiology as well as the molecular and pathological mechanisms involved in the neuropsychiatric side-effects of AAS abuse are still unclear, further research is needed in this field. In addition, diagnostically reliable tests for AAS abuse should be standardized. In this regard, to prevent the use of AASs, public health measures in all settings are crucial. These measures consist of improved knowledge among healthcare workers, proper doping screening tests, educational interventions, and updated legislation.
Purpose: To analyse the effect of resistance training (RT) performed until volitional failure with low-, moderate- and high-loads on muscle hypertrophy and muscle strength in healthy adults; and assess the possible participant-, design-, and training-related covariates which may affect the adaptations.
Methods: Using PRISMA guidelines, MEDLINE, CINAHL, EMBASE, SPORTDiscus, and Web of Science databases were searched. Including only studies that performed sets to volitional failure, the effects of low- (>15 RM), moderate- (9-15 RM), and high-load (≤8 RM) RT were examined in healthy adults. Network meta-analysis was undertaken to calculate the standardised mean difference (SMD) between RT loads in overall and subgroup analysis involving studies deemed high-quality. Associations between participant-, design-, and training-related covariates with SMD's were assessed by univariate and multivariate network meta-regression analysis.
Results: Twenty-eight studies involving 747 healthy adults were included. Although no differences in muscle hypertrophy between RT loads were found in overall (P= .113 - .469) or subgroup analysis (P= .871 - .995), greater effects were observed in untrained participants (P= .033), and participants with some training background who undertook more RT sessions (P= .031 - .045). Muscle strength improvement was superior for both high-load and moderate-load compared to low-load RT in overall and subgroup analysis (SMD= 0.60 - 0.63 and 0.34 - 0.35, respectively; P< .001 - .003), with a non-significant but superior effect for high- compared to moderate-load (SMD= 0.26 - 0.28, P= .068).
Conclusion: While muscle hypertrophy improvements appear to be load independent, increases in muscle strength are superior in high-load RT programs. Untrained participants exhibit greater muscle hypertrophy while undertaking more RT sessions provides superior gains in those with previous training experience.
The purpose of this systematic review was to evaluate the evidence surrounding the implementation of inter-set strategies to optimize acute resistance training performance. Searches of PubMed/MEDLINE, Scopus and SPORTDiscus electronic databases were conducted. Studies that met the following criteria were included: (i) compared an inter-set strategy with a traditional passive rest interval in resistance training, (ii) the assessed outcomes included performance or physiological responses, (iii) resistance training was performed in a traditional dynamic fashion, (iv) the study had an acute design, and (v) was published in English and in a peer-reviewed journal. A total of 26 studies were included in the review. When a given inter-set strategy was employed, several studies reported improvements in the number of performed repetitions (i.e., greater total volume load), attenuation of the loss in velocity and power, reduced lactate levels, and in some cases, a decrease in perceived exertion. Dynamic agonist/static antagonist stretching, cooling, aerobic exercise, vibration and individualized heart-rate (HR) based intervals appear to be the most effective strategies. However, the heterogeneity between study designs and methodologies suggests that careful consideration should be given to the type and specific application of the inter-set method being employed. Given the acute nature of studies, extrapolation to any long-term benefits of employing a given inter-set strategy remains limited. Collectively, coaches and sports scientists may consider using the most effective strategies based on practicality and equipment availability to optimize performance during the resistance training component of strength and conditioning programs.
The purpose of this paper was to systematically review the current literature and elucidate the effects of total weekly resistance training (RT) volume on changes in measures of muscle mass via meta-regression. The final analysis comprised 34 treatment groups from 15 studies. Outcomes for weekly sets as a continuous variable showed a significant effect of volume on changes in muscle size (P = 0.002). Each additional set was associated with an increase in effect size (ES) of 0.023 corresponding to an increase in the percentage gain by 0.37%. Outcomes for weekly sets categorised as lower or higher within each study showed a significant effect of volume on changes in muscle size (P = 0.03); the ES difference between higher and lower volumes was 0.241, which equated to a percentage gain difference of 3.9%. Outcomes for weekly sets as a three-level categorical variable (<5, 5-9 and 10+ per muscle) showed a trend for an effect of weekly sets (P = 0.074). The findings indicate a graded dose-response relationship whereby increases in RT volume produce greater gains in muscle hypertrophy.
RATINGS OF PERCEIVED EXERTION ARE A VALID METHOD OF ESTIMATING THE INTENSITY OF A RESISTANCE TRAINING EXERCISE OR SESSION. SCORES ARE GIVEN AFTER COMPLETION OF AN EXERCISE OR TRAINING SESSION FOR THE PURPOSES OF ATHLETE MONITORING. HOWEVER, A NEWLY DEVELOPED SCALE BASED ON HOW MANY REPETITIONS ARE REMAINING AT THE COMPLETION OF A SET MAY BE A MORE PRECISE TOOL. THIS APPROACH ADJUSTS LOADS AUTOMATICALLY TO MATCH ATHLETE CAPABILITIES ON A SET-TO-SET BASIS AND MAY MORE ACCURATELY GAUGE INTENSITY AT NEAR-LIMIT LOADS. THIS ARTICLE OUTLINES HOW TO INCORPORATE THIS NOVEL SCALE INTO A TRAINING PLAN.
Many sports involve repeated bouts of high-intensity exercise. High-intensity exercise is compromised, however, by the early onset of exercise-induced fatigue. Metabolic by-products, ion dysbalance and amount of phosphocreatine are considered the main peripheral causes of fatigue during high-intensity exercise. Intake of nutritional ergogenic aids is commonplace to enhance performance of high-intensity exercise by offsetting the potential mechanisms of fatigue. Creatine, probably one of the best known nutritional aids to enhance performance of high-intensity exercise, has convincingly substantiated its ergogenic potential. Although multi-ingredient supplements are now common, the justification for effectiveness is mostly based on observations with single intake of those ingredients. In this narrative review, the main focus is on the evidence of the effect of co-ingestion of ergogenic aids on performance of high intensity exercise for which the single intake has shown beneficial effects on high-intensity performance.
Arterio-venous anastomoses (AVAs) are direct connections between small arteries and small veins. In humans they are numerous in the glabrous skin of the hands and feet. The AVAs are short vessel segments with a large inner diameter and a very thick muscular wall. They are densely innervated by adrenergic axons. When they are open, they provide a low-resistance connection between arteries and veins, shunting blood directly into the venous plexuses of the limbs.The AVAs play an important role in temperature regulation in humans in their thermoneutral zone, which for a naked resting human is about 26°C to 36°C, but lower when active and clothed. From the temperature control center in the hypothalamus, bursts of nerve impulses are sent simultaneously to all AVAs. The AVAs are all closed near the lower end and all open near the upper end of the thermoneutral zone. The small veins in the skin of the arms and legs are also contracted near the lower end of the thermoneutral zone and relax to a wider cross section as the ambient temperature rises. At the cold end of the thermoneutral range, the blood returns to the heart through the deep veins and cools the arterial blood through a countercurrent mechanism. As the ambient temperature rises, more blood is returned through the superficial venous plexuses and veins and heats the skin surface of the full length of the four limbs. This skin surface is responsible for a large part of the loss of heat from the body towards the upper end of the thermoneutral zone.
The purpose of this investigation was to assess the effect of resistance exercise performed to volitional failure on ratings of perceived exertion (RPE) using power as an indication of fatigue. 12 male participants (M age= 21.9 yr., SD = 1.3) performed one set of back squats at three different intensities (50%, 70%, and 90% of one repetition maximum) for both a pre-determined number of repetitions (3) and to volitional failure. RPE was significantly different between sets at 50%, 70%, and 90% when performed to a pre-determined number of repetitions, but not during volitional failure. A decrease in power between the first and the last repetitions in the volitional failure sets suggests that fatigue may confound the relationship between RPE and intensity.
We previously reported that cold application to the palms between sets of high intensity bench press exercise produces an ergogenic effect in men. In this study we hypothesized that palm cooling or heating during rest intervals between high intensity weight training sets will increase total repetitions and exercise volume-load (kg) in resistance trained female subjects in a thermo-neutral environment. Eight female subjects (mean±SD, age = 25±6 yr, height = 160±6 cm, body mass = 56±7 kg, 1RM = 52±6 kg, weight training experience = 6±2 yr) completed 4 sets of 85% 1RM bench press exercise to failure, with 3 min rest intervals. Exercise trials were performed in counterbalanced order on 3 days, separated by at least 3 days in ThermoNeutral (TN), Palm Heating (PH), and Palm Cooling (PC) conditions. Heating and cooling were applied by placing both hands in a hand cooling device with the hand plate set to 45 °C for heating and 10 °C for cooling. Data were analyzed using a 2-factor repeated measures ANOVA and Tukey's post hoc tests. PC repetitions were significantly higher than TN during the 2nd set and PH repetitions were significantly higher than TN during the 4th set. Total exercise volume-load (kg) for both PC (1387±358) and PH (1349±267) were significantly higher than TN (1187±262). In women, both heating and cooling of the palms between sets of resistance exercise increased the total exercise volume-load performed. This ergogenic response to a peripheral sensory input is consistent with the central governor theory of muscular fatigue.
The widespread belief that local cooling impairs short-term, strenuous exercise performance is controversial. Eighteen original investigations involving cooling before and intermittent cooling during short-term, intensive exercise are summarized in this review. Previous literature examining short-term intensive exercise and local cooling primarily has been limited to the effects on muscle performance immediately or within minutes following cold application. Most previous cooling studies used equal and longer than 10 minutes of pre-cooling, and found that cooling reduced strength, performance and endurance. Because short duration, high intensity exercise requires adequate warm-up to prepare for optimal performance, prolonged pre-cooling is not an effective method to prepare for this type of exercise. The literature related to the effect of acute local cooling immediately before short duration, high intensity isotonic exercise such as weight lifting is limited. However, local intermittent cooling during short-term, high intense exercise may provide possible beneficial effects; first, by pain reduction, caused by an "irritation effect" from hand thermal receptors which block pain sensation, or second, by a cooling effect, whereby stimulation of hand thermal receptors or a slight lowering of blood temperature might alter central fatigue.
The depression in force and/or velocity associated with muscular fatigue can be the result of a failure at any level, from the initial events in the motor cortex of the brain to the formation of an actomyosin cross-bridge in the muscle cell. Since all the force and motion generated by muscle ultimately derives from the cyclical interaction of actin and myosin, researchers have focused heavily on the impact of the accumulation of intracellular metabolites [e.g., Pi, H⁺ and adenosine diphoshphate (ADP)] on the function these contractile proteins. At saturating Ca⁺⁺ levels, elevated Pi appears to be the primary cause for the loss in maximal isometric force, while increased [H⁺] and possibly ADP act to slow unloaded shortening velocity in single muscle fibers, suggesting a causative role in muscular fatigue. However the precise mechanisms through which these metabolites might affect the individual function of the contractile proteins remain unclear because intact muscle is a highly complex structure. To simplify problem isolated actin and myosin have been studied in the in vitro motility assay and more recently the single molecule laser trap assay with the findings showing that both Pi and H⁺ alter single actomyosin function in unique ways. In addition to these new insights, we are also gaining important information about the roles played by the muscle regulatory proteins troponin (Tn) and tropomyosin (Tm) in the fatigue process. In vitro studies, suggest that both the acidosis and elevated levels of Pi can inhibit velocity and force at sub-saturating levels of Ca⁺⁺ in the presence of Tn and Tm and that this inhibition can be greater than that observed in the absence of regulation. To understand the molecular basis of the role of regulatory proteins in the fatigue process researchers are taking advantage of modern molecular biological techniques to manipulate the structure and function of Tn/Tm. These efforts are beginning to reveal the relevant structures and how their functions might be altered during fatigue. Thus, it is a very exciting time to study muscle fatigue because the technological advances occurring in the fields of biophysics and molecular biology are providing researchers with the ability to directly test long held hypotheses and consequently reshaping our understanding of this age-old question.
Body core cooling via the palm of a hand increases work volume during resistive exercise. We asked: (a) "Is there a correlation between elevated core temperatures and fatigue onset during resistive exercise?" and (b) "Does palm cooling between sets of resistive exercise affect strength and work volume training responses?" Core temperature was manipulated by 30-45 minutes of fixed load and duration treadmill exercise in the heat with or without palm cooling. Work volume was then assessed by 4 sets of fixed load bench press exercises. Core temperatures were reduced and work volumes increased after palm cooling (Control: Tes = 39.0 ± 0.1° C, 36 ± 7 reps vs. Cooling: Tes = 38.4 ± 0.2° C, 42 ± 7 reps, mean ± SD, n = 8, p < 0.001). In separate experiments, the impact of palm cooling on work volume and strength training responses were assessed. The participants completed biweekly bench press or pull-up exercises for multiple successive weeks. Palm cooling was applied for 3 minutes between sets of exercise. Over 3 weeks of bench press training, palm cooling increased work volume by 40% (vs. 13% with no treatment; n = 8, p < 0.05). Over 6 weeks of pull-up training, palm cooling increased work volume by 144% in pull-up experienced subjects (vs. 5% over 2 weeks with no treatment; n = 7, p < 0.001) and by 80% in pull-up naïve subjects (vs. 20% with no treatment; n = 11, p < 0.01). Strength (1 repetition maximum) increased 22% over 10 weeks of pyramid bench press training (4 weeks with no treatment followed by 6 weeks with palm cooling; n = 10, p < 0.001). These results verify previous observations about the effects of palm cooling on work volume, demonstrate a link between core temperature and fatigue onset during resistive exercise, and suggest a novel means for improving strength and work volume training responses.
Compared to aerobic training (AT), resistance training (RT) has received far less attention as a prescription for general health. However, RT is as effective as AT in lowering risk for cardiovascular disease, diabetes, and other diseases. There is a clear ability of RT, in contrast to AT, to promote gains, maintenance, or slow loss of skeletal muscle mass/strength. Thus, as an antisarcopenic exercise treatment, RT is of greater benefit than AT; given the aging of our population, this is of primary importance. In our view, a substantial barrier to greater adoption of RT is the incorrectly perceived importance of variables such as external load, intensity, and volume, leading to complex, difficult-to-follow regimes. We propose a more feasible and easier-to-adhere-to paradigm for RT that could affect how RT is viewed and adopted as a prescription for public health.
Local cooling can induce an ergogenic effect during a short-term intense exercise. One proposed method of personal cooling involves heat extraction from the palm.
In this study, we hypothesized that local palm cooling (PC) during rest intervals between progressive weight training sets will increase total repetitions and exercise volume in resistance-trained subjects exercising in a thermoneutral (TN) environment.
Sixteen male subjects (mean +/- SD; age = 26 +/- 6 yr, height = 178 +/- 7 cm, body mass = 81.5 +/- 11.3 kg, one-repetition maximum (1RM) bench press = 123.5 +/- 12.6 kg, weight training experience = 10 +/- 6 yr) performed four sets of 85% 1RM bench press exercise to fatigue, with 3-min rest intervals. Exercise trials were performed in a counterbalanced order for 3 d, separated by at least 3 d: TN, palm heating (PH), and PC. Heating and cooling were applied by placing the hand in a device called the rapid thermal exchanger, set to 45 degrees C for heating or 10 degrees C for cooling. This device heats or cools the palm while negative pressure (-35 to -45 mm Hg) is applied around the hand.
Total exercise volume during the four PC sets (2480 +/- 636 kg) was significantly higher than that during TN (1972 +/- 632 kg) and PH sets (2156 +/- 668 kg, P < 0.01). The RMS of the surface EMG with PC exercise was higher (P < 0.01), whereas esophageal temperature (P < 0.05) and RPE (P < 0.05) were lower during PC compared with TN and PH.
PC from 35 degrees C to 20 degrees C temporarily overrides fatigue mechanism(s) during intense intermittent resistance exercise. The mechanisms for this ergogenic function remain unknown.
The use of performance- and image-enhancing drugs/substances (PIED) outside elite sports appears to be increasing, although the current knowledge of the nature of PIED use among recreational athletes is scarce. The present study analyzed enquiries that were submitted to the Danish Anti Doping Agency (ADD) over an 18-month period, to gain knowledge of PIED use among individuals who exercise recreationally in Denmark. One thousand three hundred ninety eight queries were examined with respect to the age and gender of the enquirer, affiliation to sport or exercise and substance in question. The key findings were that the ADD information service is generally used by males in their mid-20s who exercise in gyms and are not engaged in competitive sports. Approximately 15% of the enquirers were users of anabolic androgenic steroids (AAS) or other substances banned within elite sports by the World Anti Doping Agency, and an additional 15% considered using such substances. The present results suggest that there is a pronounced interest in the use of AAS and other PIEDs among Danish gym members.
Insulation reduces heat exchange between a body and the environment. Glabrous (nonhairy) skin surfaces (palms of the hands, soles of the feet, face, and ears) constitute a small percentage of total body surface area but contain specialized vascular structures that facilitate heat loss. We have previously reported that cooling the glabrous skin surfaces is effective in alleviating heat stress and that the application of local subatmospheric pressure enhances the effect. In this paper, we compare the effects of cooling multiple glabrous skin surfaces with and without vacuum on thermal recovery in heavily insulated heat-stressed individuals. Esophageal temperatures (T(es)) and heart rates were monitored throughout the trials. Water loss was determined from pre- and post-trial nude weights. Treadmill exercise (5.6 km/h, 9-16% slope, and 25-45 min duration) in a hot environment (41.5 degrees C, 20-30% relative humidity) while wearing insulating pants and jackets was used to induce heat stress (T(es)>or=39 degrees C). For postexercise recovery, the subjects donned additional insulation (a balaclava, winter gloves, and impermeable boot covers) and rested in the hot environment for 60 min. Postexercise cooling treatments included control (no cooling) or the application of a 10 degrees C closed water circulating system to (a) the hand(s) with or without application of a local subatmospheric pressure, (b) the face, (c) the feet, or (d) multiple glabrous skin regions. Following exercise induction of heat stress in heavily insulated subjects, the rate of recovery of T(es) was 0.4+/-0.2 degrees C/h(n=12), but with application of cooling to one hand, the rate was 0.8+/-0.3 degrees C/h(n=12), and with one hand cooling with subatmospheric pressure, the rate was 1.0+/-0.2 degrees C/h(n=12). Cooling alone yielded two responses, one resembling that of cooling with subatmospheric pressure (n=8) and one resembling that of no cooling (n=4). The effect of treating multiple surfaces was additive (no cooling, DeltaT(es)=-0.4+/-0.2 degrees C; one hand, -0.9+/-0.3 degrees C; face, -1.0+/-0.3 degrees C; two hands, -1.3+/-0.1 degrees C; two feet, -1.3+/-0.3 degrees C; and face, feet, and hands, -1.6+/-0.2 degrees C). Cooling treatments had a similar effect on water loss and final resting heart rate. In heat-stressed resting subjects, cooling the glabrous skin regions was effective in lowering T(es). Under this protocol, the application of local subatmospheric pressure did not significantly increase heat transfer per se but, presumably, increased the likelihood of an effect.
This two-part study tested the hypotheses that the use of a new cooling device, purported to extract heat from the body core through the palm of the hand, would (a) attenuate core temperature rise during submaximal exercise in the heat, thereby suppressing exercise-associated metabolic changes, and (b) facilitate a higher sustained workload, thus shortening the completion time of a time-trial performance test.
In Study 1, 8 male triathletes (age 27.9 +/- 2.0 yrs, mass 77.2 +/- 3.1 kg, VO2peak 59.0 +/- 4.1 ml x min(-1) x kg(-1)) cycled for 1 hr at the same absolute workload (approximately 60% VO2peak) in a heated room (31.9 +/- 0.1 degrees C, 24 +/- 1% humidity) on two occasions counterbalanced for cooling (C) or noncooling (NC). In Study 2, 8 similar subjects (age 26.9 +/- 2.0 yrs, mass 75.2 +/- 3.7 kg, VO2peak 54.1 +/- 3.1 ml x min(-1) x kg(-1)) performed two 30-km cycling time-trial performance tests under the same conditions (C(T), NC(T)).
In Study 1, cooling attenuated the rise in tympanic temperature (T(TY)) (1.2 +/- 0.2 vs. 1.8 +/- 0.2 degrees C; p < 0.01) and lowered mean oxygen consumption (VO2, 2.4 +/- 0.1 vs. 2.7 +/- 0.1 L x min(-1); p < 0.05) and blood lactate (1.7 +/- 0.2 vs. 2.2 +/- 0.2 mmol x L(-1); p < 0.01) during exercise. There were no significant differences in respiratory exchange ratio (RER), blood glucose, heart rate (HR), face temperature (T(F)), or back temperature (T(B)) between NC and C. In Study 2, time to complete 30 km was 6 +/- 1% less with cooling than without cooling (60.9 +/- 2.0 vs. 64.9 +/- 2.6 min; p < 0.01). During the last 20% of C(T), subjects sustained a workload that was 14 +/- 5% (p = 0.06) higher than NC(T) at the same T(TY) and HR.
Heat extraction through the hand during cycle ergometer exercise in the heat can (a) lower T(TY), lactate concentration, and VO2 during a submaximal set-workload test and (b) reduce the time it takes to complete a 30-km time-trial test.
In situations where the accumulation of internal heat limits physical performance, enhanced heat extraction from the body should improve performance capacity. The combined application of local subatmospheric pressure (35-45 mmHg) to an entire hand (to increase blood volume) and a heat sink (18-22 degrees C) to the palmar surface were used to draw heat out of the circulating blood. Subjects walked uphill (5.63 km/h) on a treadmill in a 40 degree C environment. Slopes of the treadmill were held constant during paired experimental trials (with and without the device). Heat extraction attenuated the rate of esophageal temperature rise during exercise (2.1 +/- 0.4 degrees and 2.9 +/- 0.5 degrees C/h, mean +/- SE, with and without the device, respectively; n = 8) and increased exercise duration (46.1 +/- 3.4 and 32.3 +/- 1.7 min with and without the device, respectively; n = 18). Hand cooling alone had little effect on exercise duration (34.1 +/- 3.0, 38.0 +/- 3.5, and 57.0 +/- 6.4 min, for control, cooling only, and cooling, and subatmospheric pressure, respectively; n = 6). In a longer term study, nine subjects participated in two or four trials per week for 8 wk. The individual workloads (treadmill slope) were varied weekly. Use of the device had a beneficial effect on exercise endurance at all workloads, but the benefit proportionally decreased at higher workloads. It is concluded that heat can be efficiently removed from the body by using the described technology and that such treatment can provide a substantial performance benefit in thermally stressful conditions.
McMahon, G, and Kennedy, R. The effects of palm cooling on physiological and metabolic responses, exercise performance, and total volume during high-intensity bench press exercise in resistance-trained men. J Strength Cond Res XX(X): 000-000, 2023-Previous research suggests that cooling distal to the working agonist muscles during the interset rest periods of high-intensity resistance exercise may facilitate improved performance by means of improving metabolic conditions of contractile machinery. However, these studies have not directly measured indicators of metabolic conditions. Therefore, the aim of this study was to compare 2 palm-cooling conditions with a thermoneutral condition during high-intensity resistance exercise and subsequent effects on physiological and metabolic responses and exercise performance. Eleven healthy, resistance-trained, young men (20-36 years old) performed 4 sets of bench press exercise to exhaustion at 80% 1 repetition maximum each separated by 3 minutes of passive recovery. Palm cooling (10° C [TEN] or 15° C [FTN]) or thermoneutral (28° C [CON]) condition was applied for 60 seconds during the recovery interval of each set in a randomized, double-blind fashion, with 4 days recovery between the experimental conditions. There were no differences (p > 0.05) in volume load between the experimental conditions across all sets. Mean repetition velocity and force of the bench press declined significantly following set 1 in all conditions (p < 0.05), but there were no differences between the conditions. Lactate, heart rate, and rating of perceived exertion systematically increased from sets 1 to 4; however, there were no significant differences (p > 0.05) between any of the conditions. Palm cooling at either 10 or 15° C had no observable effects on physiological and metabolic responses during exercise, nor has it any effect on bench press performance or volume load compared with a thermoneutral condition. Therefore, cooling cannot be currently recommended as an ergogenic strategy to enhance acute bench press performance or mitigate fatigue during high-intensity resistance training.
Gel pack temperatures were compared for responses to thermal, physiological, perceptual, and ergogenic indices from healthy women (n = 12) and men (n = 8). They did three rowing workouts to identify an ideal temperature. In a randomised sequence, and as subjects wore gloves equipped with mesh pouches during workouts, gel packs at one of the three average temperatures (10.6, 12.6, or 14.9°C) were inserted into the pouches. Data were collected before, during and after multi-stage workouts. Thermal, physiological, and perceptual data were each compared with three-factor (condition, gender, time) mixed effect model ANCOVAs, with repeated measures for condition and time, and gender as a between subjects' factor. Distance rowed was assessed with two-factor (condition, gender) mixed effect model ANCOVAs, with repeated measures for condition, and gender as a between subjects' factor. Within-subject contrasts was the post-hoc, and α = 0.05 denoted significance. Despite small differences for distance rowed, many dependent variables had significant inter-condition effects, whereby 10.6°C gel packs had the best thermal and physiological responses. The 10.6°C temperature 1): likely removed the most body heat, perhaps through cold-induced vasodilation and, 2): may be optimal, as it evoked the best thermal and physiological responses.
Electromyography (EMG) is a popular technique for analyzing muscle activation profiles during athletic maneuvers such as the back squat. Two methods are commonly implemented for normalizing EMG: a maximum voluntary isometric contraction (MVIC) and a dynamic maximum during the task being performed (DMVC). Although recent literature suggests DMVC may be superior, these suggestions haven’t been examined for weighted exercises. This study examined the influence of normalization method on rectus femoris, vastus medialis, and biceps femoris activations during back squats. Muscle activations were collected on twenty-seven participants (13 females, 14 males) performing one-repetition maximum (DMVC) and submaximum (80%) back squats. Data from submaximum squats were normalized to MVICs and DMVC. Data were compared using intra-class correlations over two testing days, variance ratio, and coefficients of variation. Mixed-model ANOVAs were used to elucidate the influence on intra-participant (method) and inter- (sex) subject variability (method). Reliability was “good” or “excellent” for MVIC and “excellent” for DMVC. Inter-subject variability was greater for MVIC compared to DMVC for all muscles. A significant normalization by sex interaction for both peak and mean biceps femoris activation was found. Based on our findings and current literature, normalization to DMVC is the superior method for weighted exercises.
O'Brien, IT, Kozerski, AE, Gray, WD, Chen, L, Vargas, LJ, McEnroe, CB, Vanhoover, AC, King, KM, Pantalos, GM, and Caruso, JF. Use of gloves to examine intermittent palm cooling's impact on rowing ergometry. J Strength Cond Res XX(X): 000-000, 2020-The aim of this study was to examine the use of gloves on intermittent palm cooling's impact on rowing ergometry workouts. Our methods had subjects (n = 34) complete 3 rowing ergometer workouts of up to 8 2-minute stages separated by 45- or 60-second rests. They were randomized to one of the following treatments per workout: no palm cooling (NoPC), intermittent palm cooling as they rowed (PCex), or intermittent palm cooling as they rowed and post-exercise (PCex&post). Palm cooling entailed intermittent cold (initial temperature: 8.1° C) application and totaled 10 (PCex) and 20 (PCex&post) minutes, respectively. Workouts began with 8 minutes of rest after which pre-exercise data were obtained, followed by a ten-minute warm-up and the workout, and 20 minutes of post-exercise recovery. Numerous physiological and performance variables were collected before, during, and after workouts, and each was analyzed with either a two- or three-way analysis of variance. Our results include, with a 0.05 alpha and a simple effects post hoc, the distance rowed analysis produced a significant workout effect with PCex, PCex&post > NoPC. There were also significant interworkout differences for heart rate (HR) (NoPC > PCex) and blood lactate concentration (NoPC > PCex, PCex&post). We conclude that lower HRs and blood lactate concentrations from intermittent cooling caused subjects to experience less fatigue during those workouts and enabled more work to be performed. Continued research should identify optimal cooling characteristics to expedite body heat removal. Practical applications suggest that intermittent palm cooling administered with gloves enhance performance by abating physiological markers of fatigue.
Athletes use cold water immersion, cryotherapy chambers or icing in the belief that these strategies improve postexercise recovery and promote greater adaptations to training. A number of studies have systematically investigated how regular cold water immersion influences long-term performance and muscle adaptations. The effects of regular cold water immersion after endurance or high-intensity interval training on aerobic capacity, lactate threshold, power output and time trial performance are equivocal. Evidence for changes in angiogenesis and mitochondrial biogenesis in muscle in response to regular cold water immersion is also mixed. More consistent evidence is available that regular cold water immersion after strength training attenuates gains in muscle mass and strength. These effects are attributable to reduced activation of satellite cells, ribosomal biogenesis, anabolic signaling and muscle protein synthesis. Athletes use passive heating to warm up before competition or improve postexercise recovery. Emerging evidence indicates that regular exposure to ambient heat, wearing garments perfused with hot water or microwave diathermy can mimic the effects of endurance training by stimulating angiogenesis and mitochondrial biogenesis in muscle. Some passive heating applications may also mitigate muscle atrophy through their effects on mitochondrial biogenesis and muscle fiber hypertrophy. More research is needed to consolidate these findings, however. Future research in this field should focus on (1) the optimal modality, temperature, duration and frequency of cooling and heating to enhance long-term performance and muscle adaptations and (2) whether molecular and morphological changes in muscle in response to cooling and heating applications translate to improvements in exercise performance.
HIGHLIGHTS:
1) The reliance on anaerobic metabolism causes fatigue during high-intensity exercise.
2) Metabolic pathways maintain ATP at levels that do not impair contractile function.
3) Intracellular homeostasis is disrupted by metabolite accumulation, namely H+ and Pi.
4) Multifaceted and synergistic effects of H+ and Pi markedly impair muscle contraction.
5) Fatigue has a bioenergetic basis determined by the rate and extent of metabolite accumulation.
ABSTRACT:
Energetic demand from high-intensity exercise can easily exceed ATP synthesis rates of mitochondria leading to a reliance on anaerobic metabolism. The reliance on anaerobic metabolism results in the accumulation of intracellular metabolites, namely inorganic phosphate (Pi) and hydrogen (H+), that are closely associated with exercise-induced reductions in power. Cellular and molecular studies have revealed several steps where these metabolites impair contractile function demonstrating a causal role in fatigue. Elevated Pi or H+ directly inhibits force and power of the cross-bridge and decreases myofibrillar Ca2+ sensitivity, whereas Pi also inhibits Ca2+ release from the sarcoplasmic reticulum (SR). When both metabolites are elevated, they act synergistically to cause marked reductions in power, indicating that fatigue during high-intensity exercise has a bioenergetic basis.
Resistance exercise training (RET)-induced increases in voluntary 1RM strength are greater with higher loads and training by replicating (or close) the strength test. In contrast, RET-induced muscular hypertrophy is primarily mediated by intensity of effort, which is achieved by performing RET to volitional fatigue and with an internal focus on contracting a muscle throughout the exercise range of motion. In addition, RET-induced muscular hypertrophy is augmented by increasing training volume, but with diminishing returns. Other training variables such as volume-load, inter-set rest, and time under tension have negligible effects on RET-induced changes in muscle size or strength. We conclude that an uncomplicated, evidence-based approach to optimizing RET-induced changes in muscle size and strength follows the FITT principle: frequency, intensity (effort), type, and time.
Despite the fact that sports organizations and legislators have introduced various mechanisms to discourage athletes from using performance and appearance enhancing substances a high percentage of athletes admits to their unabated application. In competitive athletics, bodybuilding and in recreational sports anabolic androgenic steroids (AAS) continue to be the substances most abused. This review summarizes the side effects of AAS abuse on organs and system functions in both sexes. High doses of AAS cause a significant increase of erythrocytes und haemoglobin concentration, which may lead to thromboembolism, intracardiac thrombosis and stroke. Long-term AAS abusers have a higher incidence of arrhythmias, atherosclerosis, concentric left-ventricular myocardial hypertrophy with impaired diastolic function and also sudden cardiac death. Changes of liver function and structure, up to hepatocellular carcinoma, have been described, mainly in cases of chronic misuse of 17α-alkylated AAS. Sleeplessness, increased irritability, depressive mood status are often observed in AAS abuse. In former AAS abusers depression, anxiety and melancholy may persist for many years. Due to negative feedback in the regulation of the hypothalamic-pituitary-gonadal axis AAS can cause reversible suppression of spermatogenesis up to azoospermia. In women the changes most often caused by AAS abuse are hirsutism, irreversible deepening of voice, dysmenorrhoea, secondary amenorrhoea with anovulation and infertility. AAS abuse notwithstanding, under clinical conditions testosterone remains the most important hormone for substitution therapy of male hypogonadism.
To examine palm cooling's (15°C) impact, subjects performed 3 four-set leg press workouts in a randomized sequence. Per workout they received 1 of 3 treatments: no palm cooling, palm cooling between sets, or palm cooling between sets and post-exercise. Dependent variables were examined with three-way ANOVAs; average power underwent a three-way ANCOVA with body fat percentage as the covariate. Simple effects analysis was our post hoc and α=0.05. Left hand skin temperatures produced a two-way interaction (no palm cooling, palm cooling between sets>palm cooling between sets and post-exercise at several time points). A "high responder" subset had their data analyzed with an additional three-way ANOVA that again produced a two-way interaction (palm cooling between sets>no palm cooling>palm cooling between sets and post-exercise at multiple time points). Blood lactate results included a two-way interaction (no palm cooling>palm cooling between sets, palm cooling between sets and post-exercise at 0 min post-exercise). Average power yielded a two-way interaction (palm cooling between sets, palm cooling between sets>no palm cooling for the fourth set). Intermittent palm cooling hastened heat removal and blood lactate clearance, as well as delayed average power decrements.
© Georg Thieme Verlag KG Stuttgart · New York.
To test whether vasomotor responses to dynamic exercise differ in glabrous and nonglabrous human skin, we determined the phase response and amplitude response of cutaneous vascular conductance in the forearm (CVCforearm), dorsal hand (CVCdorsal hand), and palm (CVCpalm) to sinusoidal exercise.
Nine healthy subjects exercised on a cycle ergometer with a constant load (35% of peak O2 uptake) for 20 min at an ambient temperature of 25 degrees C and relative humidity of 60%; for the next 40 min, they exercised with a sinusoidal load. The sinusoidal load variation ranged from 10% to 60% of peak O2 uptake over a 4-min period. Skin blood flow was monitored by laser-Doppler flowmetry. CVC was calculated from the ratio of blood flow to mean arterial pressure (MAP).
During sitting rest and exercise, CVCpalm showed consistently higher value than CVCforearm and CVCdorsal hand. During sinusoidal exercise, the amplitude in CVCpalm was 7.4 times and 3.2 times greater than those in CVCforearm and CVCdorsal hand, respectively (P < 0.05). The phase difference in CVCforearm and CVCdorsal hand were smaller than that in CVCpalm (P < 0.05).
These findings of significant differences in phase and amplitude of responses in CVC between glabrous and nonglabrous skin during cyclic changes of dynamic exercise load suggest functionally important differences in the reflex control of these regions of skin.
books/computational-intelligence-inelectromyography-analysis-a-perspective-oncurrent-applications-and-future-challenges/ normalization-of-emg-signals-to-normalize-ornot-to-normalize-and-what-to-normalize-to
- M Halaki
- K Gi
Halaki M, Gi K. Normalization of EMG Signals:
To Normalize or Not to Normalize and What to
Normalize to? Naik GR, ed. InTech, 2012.
Available at: http://www.intechopen.com/
books/computational-intelligence-inelectromyography-analysis-a-perspective-oncurrent-applications-and-future-challenges/
normalization-of-emg-signals-to-normalize-ornot-to-normalize-and-what-to-normalize-to-.
Accessed April 15, 2023.
Effects of heat removal through the
- A R Hsu
- T A Hagobian
- K A Jacobs
- H Attallah
- A L Friedlander
Hsu AR, Hagobian TA, Jacobs KA, Attallah H,
Friedlander AL. Effects of heat removal through the