Effect of Gear Ratio and Cadence on Gross Efficiency and Pedal Force Effectiveness during Multistage Graded Cycling Test Using a Road Racing Bicycle.

Gross efficiency (GE) and the index of pedal force effectiveness (IFE) are important factors that enhance cyclists' performance; however, the effects of changing pedal force (gear ratio) and cadence on these indices while riding on a road racing bicycle are poorly investigated. This study aimed to examine the effect of changing gear ratio or cadence on GE and IFE using a road racing bicycle. Nine male cyclists completed graded submaximal cycling tests (five stages of 4 min submaximal cycling sessions with 1 min passive rest intervals). The work rate of each stage was determined using two principles: changing gear ratio at a fixed cadence and changing cadence at a fixed gear ratio. We determined GE and IFE using respiratory variables and pedal reaction forces, respectively. Increasing the gear ratio improved GE, and was associated with the IFE. Although increasing the cadence slightly improved GE from the initial level, the increased values then mostly maintained. IFE was almost stable even when cadence increased. Moreover, no significant correlation was observed between the changes in GE and IFE accompanied by increasing cadence. Our data indicate that an increasing gear ratio, but not cadence, may affect GE and IFE while riding on a road racing bicycle.

Stepwise Load Reduction Training: A New Training Concept for Skeletal Muscle and Energy Systems.

An increased ability to supply energy to skeletal muscle is expected to contribute to greater athletic performance, and therefore, a variety of training methods are used for improving these energy supply systems. These methods are classified into two broad categories: a bout of continuous exercise at a given load/intensity and intermittent bouts of exercise at a given load/intensity with recovery intervals. Interestingly, recent work suggests that a training method which starts at a high load/intensity and gradually decreases the exercise load/intensity within a given training set (stepwise load reduction training) may provide a range of adaptations. In resistance training, the load starts off high and is then reduced as the set continues which is expected to simultaneously increase muscle strength, endurance, and size. In training focused on aerobic and anaerobic metabolic systems, intensity starts off high and is then reduced as the exercise continues which is expected to simultaneously increase maximal anaerobic power, anaerobic capacity, and aerobic capacity. Because stepwise load reduction training has no recovery intervals between each load/intensity, the training effects are achieved within a short time per session (several minutes). However, only minimal evidence exists to support the effects of stepwise load reduction training; therefore, further studies with larger samples are needed.

The Effects of Transdermal Nicotine Patches on the Cardiorespiratory and Lactate Responses During Exercise from Light to Moderate Intensity: Implications for Exercise Prescription during Smoking Cessation.

Background and objectives: Exercise can help ease withdrawal symptoms of smokers. However, there is little information about the physiological responses, such as cardiorespiratory and lactate (La) responses, during exercise from light to moderate intensity combined with transdermal nicotine patches (TNPs) in smokers. This study aimed to investigate the effect of TNPs on the cardiorespiratory and La responses during exercise at light to moderate intensity. Materials and Methods: Fourteen young men (8 non-smokers, 6 current smokers) aged 20 to 26 years participated in this study. They performed an incremental graded submaximal exercise test using an electromagnetic cycle ergometer set from 30 to 210 W with (TNP condition) or without a TNP (control condition) in a random order. The TNP was applied to the left arm 8-10 h prior to starting the exercise to achieve the peak level of blood nicotine concentration. Heart rate (HR), rate of perceived exertion (RPE), oxygen consumption (VO2), ventilation (VE), and blood La at rest and during exercise were measured and analyzed. Results: The HR at rest was significantly higher in the TNP condition than in the control condition (TNP; 74.7 ± 13.8 bpm, control; 65.3 ± 10.8 bpm, p < 0.001). There was no interaction (condition × exercise intensity) between any of the variables, and VO2, VE, RPE, and La during exercise were not significantly different between the conditions. However, HR during exercise was 6.7 bpm higher on average in the TNP condition. Conclusions: The HR during exercise was greater at light to moderate intensity with a TNP. Our study results will guide clinicians or health professionals when prescribing exercise programs combined with TNPs for healthy young smokers.

Heart Rate Responses and Exercise Intensity During A Prolonged 4-Hour Individual Cycling Race among Japanese Recreational Cyclists.

Heart rate (HR) during different endurance cycling races and events are investigated for professional cyclist, however, enduro races to compete for total laps and distance covered within a fixed time using a circuit course has not yet been investigated. This study examined the heart rate (HR) and exercise intensity during an enduro cycling race. Ten male Japanese amateur cyclists performed cycling individually for at least 2 consecutive hours. HR was measured using an HR monitor during the race, and we estimated the energy expenditure (EE) during the race using the HR-VO2 relationship in advance. Exercise intensities were defined as percentages of HRmax based on ACSM exercise guideline as follows: moderate intensity, 64-76% HRmax; vigorous intensity, 77-95% HRmax. The HR during the race was 158.9 ± 10.6 bpm (86.4 ± 2.2% HRmax), and exercise intensity is categorized as vigorous intensity. The EE during the race using HR-VO2 relationship were 12.9 ± 1.2 kcal/kg/hr, which would require a large energy expenditure (EE) during the race. However, energy cost was 0.36 ± 0.04 kcal/kg/km regardless of total distance. The findings indicate that enduro cycling racing is categorized as vigorous intensity (>77% HRmax) for healthy male recreational cyclists though, cycling is an efficient form of transportation.

Effects of shortening and lengthening resistance exercise with low-intensity on physical fitness and muscular function in senior adults / Efeitos de exercícios resistivos de encurtamento e alongamento, em baixa intensidade, sobre condicionamento e função muscular em adultos sênior

OBJECTIVE: To identify effects of shortening and lengthening low-intensity resistance exercise together with aerobic exercise on physical fitness and muscular strength in senior adults. METHOD: Seventeen males (58-72yrs) and sixteen females (58-68yrs) participated in this study: seven male and six female as control subjects, ten male and ten female as exercise subjects: these subjects completed an 8-week training program (two times/week) consisting of 15 minutes of aerobike exercise at 50% of VO2max and six shortening-lengthening resistance exercises (3 exercises for upper body and 3 exercises for lower body). The subjects exercised resistance training (5 sec for shortening, 5 sec for lengthening) at 50% of one repetition maximum. Primary outcome measures included physical fitness tests (grip strength, sit-ups, sit-and-reach, 6 minutes of walking, single-leg balance test with open eyes), timed up-and-go test (UP&GO), and one repetition maximum of the same six exercises. This study examined joint angle of knee flexion and elbow flexion, visual analog scale, and muscular strength test to identify delayed onset muscle soreness. RESULTS: The resting blood pressures in both exercising groups were significantly decreased after 16 sessions of exercise intervention (p < 0.05). The training group significantly increased muscular strength and improved physical fitness, UP&GO, and one repetition maximum of 6 resistance exercises (p < 0.05). The combined exercise did not induce delayed onset muscle soreness. CONCLUSION: The present study showed that the combined shortening and lengthening resistance training with aerobic exercise in senior male and female adults was effective in decreasing blood pressure and increasing muscular strength and physical fitness.

OBJETIVO: Identificar os efeitos de encurtamento e alongamento através de exercício resistivo de baixa intensidade, juntamente com exercício aeróbico sobre a aptidão física e força muscular em idosos. MÉTODO: Dezessete homens (58-72 anos) e dezesseis mulheres (58-68 anos) participaram deste estudo: 7 homens e 6 mulheres como controles, 10 homens e 10 mulheres submetidos aos exercícios: um programa de treinamento bissemanal de 8 semanas, consistindo em dez minutos de aerobike a 50% do VO2max e seis exercícios de alongamento/encurtamento (três para membros superiores e três para membros inferiores). Cada exercido foi repetido quinze vezes (50% de Uma-Repetição-Máxima - 1RM) com 5 seg para encurtamento e 5 seg para alongamento). Foram medidos: força de preensão, sit-ups, sentar-e-alcançar, 6 minutos de caminhada, teste de equilíbrio de single-leg com os olhos abertos), teste up-and-go (UP & GO), 1RM dos mesmos seis exercícios, ângulo articular de flexão do joelho e flexão de cotovelo, escala analógica visual, e teste de força muscular para identificar dor muscular tardia. RESULTADOS: A pressão arterial em repouso do grupo exercício apresentou diminuição significativa após as 16 sessões de exercício. O grupo de treinamento aumentou significativamente a força muscular com melhoria da aptidão física, UP & GO, e uma repetição máxima de 6 exercícios de resistência. O exercício combinado não induziu dor muscular tardia. CONCLUSÃO: O presente estudo mostrou que o encurtamento/alongamento combinado com o exercício aeróbico em adultos idosos do sexo masculino e feminino foi eficaz para a diminuição da pressão arterial e aumento de força muscular e aptidão física.

Oxygen uptake, heart rate, perceived exertion, and integrated electromyogram of the lower and upper extremities during level and Nordic walking on a treadmill.

The purpose of this study was to characterize responses in oxygen uptake ( V·O(2)), heart rate (HR), perceived exertion (OMNI scale) and integrated electromyogram (iEMG) readings during incremental Nordic walking (NW) and level walking (LW) on a treadmill. Ten healthy adults (four men, six women), who regularly engaged in physical activity in their daily lives, were enrolled in the study. All subjects were familiar with NW. Each subject began walking at 60 m/min for 3 minutes, with incremental increases of 10 m/min every 2 minutes up to 120 m/min V·O(2), V·(E) and HR were measured every 30 seconds, and the OMNI scale was used during the final 15 seconds of each exercise. EMG readings were recorded from the triceps brachii, vastus lateralis, biceps femoris, gastrocnemius, and tibialis anterior muscles. V·O(2) was significantly higher during NW than during LW, with the exception of the speed of 70 m/min (P < 0.01). V·E and HR were higher during NW than LW at all walking speeds (P < 0.05 to 0.001). OMNI scale of the upper extremities was significantly higher during NW than during LW at all speeds (P < 0.05). Furthermore, the iEMG reading for the VL was lower during NW than during LW at all walking speeds, while the iEMG reading for the BF and GA muscles were significantly lower during NW than LW at some speeds. These data suggest that the use of poles in NW attenuates muscle activity in the lower extremities during the stance and push-off phases, and decreases that of the lower extremities and increase energy expenditure of the upper body and respiratory system at certain walking speeds.

Risk factors for frequent work-related burn and cut injuries and low back pain among commercial kitchen workers in Japan.

This study investigated risk factors for frequent work-related burn and cut injuries and low back pain (LBP) among kitchen workers including personal, work-related and environmental factors. Subjects were 991 kitchen workers in 103 schools, 17 hospitals and nursing homes, and 6 restaurants in central Japan. A cross-sectional survey was carried out using a structured self-administered questionnaire. Logistic regression models were used to examine associations between frequent injuries/LBP and risk factors. The effective response rate was 75.1% (n=744), the mean age was 40.7 (SD 11.7) and 77.2% were female. Burn injury was associated with a smaller kitchen (OR 1.94; 95%CI, 1.13-3.33), and gas kitchens rather than electric kitchens (OR 2.30; 95%CI, 1.17-4.52). LBP was associated with female gender (OR 2.46; 95%CI, 1.37-4.43), high body height (>160 cm) (OR 2.03; 95%CI, 1.22-3.36), and large number of meals produced per person (≥ 150 meals) (OR 1.83; 95%CI, 1.12-3.00). The results of this study suggest that securing adequate work space and introducing electric kitchen systems may reduce the risk to kitchen workers, as well as the importance of adequate height of cooking equipment and selecting an appropriate volume of meals to produce per person to prevent LBP in kitchen workers.

Effects of proprioceptive neuromuscular facilitation stretching and static stretching on maximal voluntary contraction.

This study was undertaken to investigate and compare the effects of proprioceptive neuromuscular facilitation (PNF) stretching and static stretching on maximal voluntary contraction (MVC). Thirteen male university students (age, 20 ± 1 years; height, 172.2 ± 4.6 cm; weight, 68.4 ± 6.7 kg; mean ± SD) completed 3 different conditions on 3 nonconsecutive days in randomized order: static stretching (SS), PNF stretching (PNF), and no stretching (control, CON). Each condition consisted of a 5-minute rest accompanied by one of the following activities: (a) control, (b) SS, or (c) PNF stretching. The hip flexion range of motion (ROM) was evaluated immediately before and after the activity. The MVC of knee flexion was then measured. Surface electromyography was recorded from the biceps femoris and vastus lateralis muscles during MVC tests and stretching. Although increases in ROM were significantly greater after PNF than after SS (p < 0.01), the decreases in MVC were similar between the 2 treatments. These results suggest that, although PNF stretching increases ROM more than SS, PNF stretching and SS is detrimental to isometric maximal strength.

Workers' load and job-related stress after a reform and work system change in a hospital kitchen in Japan.

OBJECTIVES: Many kitchen work environments are considered to be severe; however, when kitchens are reformed or work systems are changed, the question of how this influences kitchen workers and environments arises. The purpose of this study is to examine whether there was a change in workload and job-related stress for workers after a workplace environment and work system change in a hospital kitchen. METHODS: The study design is a pre-post comparison of a case, performed in 2006 and 2008. The air temperature and humidity in the workplace were measured. Regarding workload, work hours, fluid loss, heart rate, and amount of activity [metabolic equivalents of task (METs)] of 7 and 8 male subjects pre- and post-reform, respectively, were measured. Job-related stress was assessed using a self-reporting anonymous questionnaire for 53 and 45 workers pre- and post-system change, respectively. RESULTS: After the reform and work system change, the kitchen space had increased and air-conditioners had been installed. The workplace environment changes included the introduction of temperature-controlled wagons whose operators were limited to male workers. The kitchen air temperature decreased, so fluid loss in the subjects decreased significantly. However, heart rate and METs in the subjects increased significantly. As for job-related stress, although workplace environment scores improved, male workers' total job stress score increased. CONCLUSIONS: These results suggest that not only the workplace environment but also the work system influenced the workload and job stress on workers.

Effects of training volume on strength and hypertrophy in young men.

Knowledge of the effects of training volume on upper limb muscular strength and hypertrophy is rather limited. In this study, both arms of the same subject were trained in a crossover-like design with different training volumes (1 or 3 sets) to eliminate the effects of genetic variation and other individual differences. The purpose of this study was to investigate the effects of training volume on muscular strength and hypertrophy in sedentary, untrained young Japanese men. Eight subjects (age, 25.0 ± 2.1 years; body mass, 64.2 ± 7.9 kg; height, 171.7 ± 5.1 cm) were recruited. The subjects trained their elbow flexor muscles twice per week for 12 consecutive weeks using a seated dumbbell preacher curl. The arms were randomly assigned to training with 1 or 3 sets. The training weight was set at 80% of 1 repetition maximum for all sets. The 3-set protocol increased cross-sectional area significantly more than did 1 set (1 set, 8.0 ± 3.7%; 3 sets, 13.3 ± 3.6%, p < 0.05). Furthermore, gains in strength with the 3-set protocol tended to be greater than those with 1 set (1 set, 20.4 ± 21.6%; 3 sets, 31.7 ± 22.0%, p = 0.076). Based on the results, the authors recommend 3 sets for sedentary untrained individuals. However, this population should incorporate light training days of 1 set into their training program to prevent overtraining and ensure adherence. The findings are relevant for the sedentary, untrained young male population and must be interpreted within the context of this study.

Theoretical study of factors affecting ball velocity in instep soccer kicking.

The objective of this study was to investigate the factors affecting ball velocity at the final instant of the impact phase (t1) in full instep soccer kicking. Five experienced male university soccer players performed maximal full instep kicks for various foot impact points using a one-step approach. The kicking motions were captured two dimensionally by a high-speed camera at 2,500 fps. The theoretical equation of the ball velocity at t1 given in the article was derived based on the impact dynamics theory. The validity of the theoretical equation was verified by comparing the theoretical relationship between the impact point and the ball velocity with the experimental one. Using this theoretical equation, the relationship between the impact point and the ball velocity was simulated. The simulation results indicated that the ball velocity is more strongly affected by the foot velocity at the initial instant of the impact phase than by other factors. The simulation results also indicated that decreasing the ankle joint reaction force during ball impact shifts the impact point that produces the greatest ball velocity to the toe side and decreasing the ankle joint torque during ball impact shifts the impact point that produces the greatest ball velocity to the ankle side.

The effects of work environments on thermal strain on workers in commercial kitchens.

The purpose of this study was to clarify the effect of working environments of different kinds of commercial kitchens on the thermal strain of kitchen workers. This study design was cross-sectional study, and data collection was performed during busy time in commercial kitchen from August to September 2006. The research subjects were 8 institutions, involving 7 cookers, and 16 men. Measured environmental variables were air temperature, radiant heat index, wet bulb globe thermometer index (WBGT) in front of the cookers, ambient temperature, and estimated ambient WBGT around the workers. The thermal strain on workers was evaluated by fluid loss, body temperatures, heart rate and amount of physical activity (METs). All average estimated ambient WBGTs in front of cookers were less than 27.5℃. The average heart rate was 107 ± 10 bpm, and average METs was 2.0 ± 0.6. The peak values of upper arm skin temperature and auditory canal temperature were less than 37.5℃. The work environments were affected by the kitchen spaces, cooling devices, heating methods, and heat sources. Even in the midsummer, if environmental temperatures were controlled adequately, estimated ambient WBGTs around workers were below the occupational exposure limit. Work environments and thermal strain on workers in commercial kitchen were not severe.

Heat stress enhances mTOR signaling after resistance exercise in human skeletal muscle.

This study investigated the effect of heat stress (HS) on mammalian target of rapamycin (mTOR) signaling involved in translation initiation after resistance exercise in human skeletal muscle. Eight young male subjects performed four sets of six maximal repetitions of knee extension exercises, with or without HS, in a randomized crossover design. HS was applied to the belly of the vastus lateralis by using a microwave therapy unit prior to and during exercise. Muscle biopsies were taken from the vastus lateralis before, immediately after, and 1 h after exercise. HS significantly increased the phosphorylation of Akt/PKB, mTOR, and ribosomal protein S6 at 1 h after exercise (P < 0.05), and the 4E-BP1 phosphorylation level, which had initially decreased with exercise, had recovered by 1 h after exercise with HS. In addition, the phosphorylation of ribosomal S6 kinase 1 was significantly increased immediately after exercise with HS (P < 0.05). These results indicate that HS enhances mTOR signaling after resistance exercise in human skeletal muscle.

Determinants of intramyocellular lipid accumulation after dietary fat loading in non-obese men.

UNLABELLED: Aims/Introduction: Accumulation of intramyocellular lipid (IMCL) is associated with insulin resistance. However, the factors affecting the change in IMCL remain to be elucidated. The aim of the present study was to determine the factors that influence the change in IMCL level after high-fat loading. MATERIALS AND METHODS: The study subjects were 37 non-obese men. Each subject consumed a high-fat diet for 3 days after a normal-fat diet for 3 days. After each diet program, IMCL levels in the tibialis anterior (TA-IMCL) and soleus (SOL-IMCL) were measured by proton magnetic resonance spectroscopy. Glucose infusion rate (GIR) was evaluated by euglycemic hyperinsulinemic clamp as an index of peripheral insulin sensitivity. RESULTS: The high-fat diet significantly increased TA-IMCL and SOL-IMCL by ∼30 and ∼20%, respectively (P < 0.05), whereas it did not significantly alter GIR. The increase in SOL-IMCL, but not in TA-IMCL, negatively correlated with serum high molecular weight (HMW)-adiponectin (r = -0.36, P < 0.05) and HMW-/total-adiponectin ratio (r = -0.46, P < 0.05). Although high-fat diet-related changes in SOL-IMCL showed high inter-individual variations, in subjects doing exercise, changes in SOL-IMCL (r = 0.55, P < 0.05) and TA-IMCL (r = 0.61, P < 0.05) positively correlated with daily physical activity level. In contrast, in sedentary subjects, changes in SOL-IMCL (r = -0.50, P < 0.01) and TA-IMCL (r = -0.48, P < 0.05) negatively correlated with daily physical activity. CONCLUSIONS: HMW-adiponectin and daily physical activity are determinants of IMCL accumulation by a high-fat diet. Intriguingly, the effect of daily physical activity on the change in IMCL depends on the level of regular exercise. (J Diabetes Invest,doi: 10.1111/j.2040-1124.2010.00091.x, 2011).

Evaluation of subjective thermal strain in different kitchen working environments using subjective judgment scales.

To elucidate the subjective thermal strain of workers in kitchen working environments, we performed a cross-sectional study involving 991 workers in 126 kitchen facilities in Japan, using a self-reporting questionnaire survey and subjective judgment scales (SJS). The ambient temperature, mean radiant temperature (MRT), and wet-bulb globe temperature (WBGT) index were measured in 10 kitchen facilities of the 126 kitchens. The association of SJS with the types of kitchen was estimated by multiple logistic regression models. Of the 991 kitchen workers, 809 (81%) responded to the questionnaire survey. Compared with the electric kitchens, the proportion of workers who perceived the room temperature as hot to very hot was significantly higher, and the ambient temperature, MRT, and WBGT were significantly higher in the gas kitchens. Compared with the electric kitchens, workers in gas kitchens had a more than fivefold (males) and tenfold (females) higher SJS adjusted for confounding factors (male odds ratio (OR), 5.13; 95% confidence interval (CI), 1.65-15.9; and female OR, 10.9; 95%CI, 3.89-30.5). Although SJS was affected by some confounding factors, our results suggest that workers in gas kitchens might be exposed to a higher heat strains than those in electric kitchens.

Numerical study of ball behavior in side-foot soccer kick based on impact dynamic theory.

This study examined the factors affecting the ball velocity and rotation for side-foot soccer kick using a numerical investigation. Five experienced male university soccer players performed side-foot kicks with various attack angles and impact points using a one-step approach. The kicking motions were captured three-dimensionally by two high-speed cameras at 2500 fps. The theoretical equations of the ball velocity and rotation were derived based on impact dynamic theory. Using the theoretical equations, the relationships of the ball velocity and rotation to the attack angle and impact point were obtained. The validity of the theoretical equations was verified by comparing the theoretical relationships with measurement values. Furthermore, simulations of the ball velocity and rotation were conducted using the theoretical equations. The theoretical relationships were in good agreement with the measurement values. The theoretical results confirmed the previously reported experimental results, and indicated that the impact point is more influential on the ball velocity than the attack angle and the attack angle is more influential on the ball rotation than the impact point. The simulation results indicated the following. The ball velocity produced by impact for all impact patterns is largely affected by the foot velocity immediately before impact but barely affected by the degree of slip between the foot and the ball. The ball rotation produced by an impact with a large attack angle is affected by the foot velocity immediately before impact and the degree of slip between the foot and the ball; however, these factors affect the ball rotation less than the attack angle.

Six-year prospective study of physical fitness and incidence of disability among community-dwelling Japanese elderly women.

AIM: To identify physical fitness factors associated with occurrence of disability requiring long-term care and reviewing physical fitness factors to identify threshold values at which future care risk is expected to rise rapidly. METHODS: This prospective cohort study included 74-88-year-old women who were living at home and who reported no disability in activities of daily living. The subjects completed 16 physical fitness tests, assessing walking ability, muscular strength, flexibility, agility and balance, and participated in a follow-up interview 6 years later. RESULTS: Among the 60 subjects who were not disabled at baseline and who participated in the 6-year follow up, 28 subjects were certified to have a disability necessitating long-term care after 6 years. Among the 16 physical fitness tests, 13 measures showed a significant association with the necessity of care. Maximum walking time and ankle dorsiflexion range of motion (ROM) were identified as main physical fitness factors associated with later necessity of care using a multiple logistic regression model. After adjustment for age, each subject's probability of occurrence of disability necessitating care was calculated using a logistic equation. The probability rose rapidly to more than 80% when 10 m maximum walking of 74-78-year-old subjects was 10 s. For 80-88-year-old subjects, the probability rose rapidly to more than 80% when the time was at 9 s. As ankle dorsiflexion ROM narrowed, the probability rose gradually. CONCLUSION: Ability to walk rapidly is an indicative main physical fitness marker for predicting the independence of elderly women.

Effects of voluntary wheel running on satellite cells in the rat plantaris muscle.

This study investigated the effects of voluntary wheel running on satellite cells in the rat plantaris muscle. Seventeen 5-week-old male Wistar rats were assigned to a control (n = 5) or training (n = 12) group. Each rat in the training group ran voluntarily in a running-wheel cage for 8 weeks. After the training period, the animals were anesthetized, and the plantaris muscles were removed, weighed, and analyzed immunohistochemically and biochemically. Although there were no significant differences in muscle weight or fiber area between the groups, the numbers of satellite cells and myonuclei per muscle fiber, percentage of satellite cells, and citrate synthase activity were significantly higher in the training group compared with the control group (p < 0.05). The percentage of satellite cells was also positively correlated with distance run in the training group (r = 0.61, p < 0.05). Voluntary running can induce an increase in the number of satellite cells without changing the mean fiber area in the rat plantaris muscle; this increase in satellite cell content is a function of distance run. Key pointsThere is no study about the effect of voluntary running on satellite cells in the rat plantaris muscle.Voluntary running training causes an increase of citrate synthase activity in the rat plantaris muscle but does not affect muscle weight and mean fiber area in the rat plantaris muscle.Voluntary running can induce an increase in the number of satellite cells without hypertrophy of the rat plantaris muscle.

Effects of heating appliances with different energy efficiencies on associations among work environments, physiological responses, and subjective evaluation of workload.

To clarify the association between heat stress, physiological responses and subjective workload evaluations in kitchens using an induction heating stove (IH stove) or gas stove. The study design was an experimental trial involving 12 young men. The trial measured ambient dry-bulb temperature, globe temperature, wet-bulb globe temperature (WBGT) and relative humidity; the subjects' weight, heart rate, blood pressure, oxygen uptake, amount of activity, body temperature, subjective awareness of heat and workload before and after mock cooking for 30 min. The IH stove insignificantly increased heat indicators in the work environment and workers showed lower oxygen uptake, skin temperature, subjective awareness of heat and workload after heat exposure. Both physiological load and subjective awareness of heat and workload were slight in kitchens using the IH stove, which provided a better work environment.