BACKGROUNDOur previous study has confirmed that one bout of exhaustion (Ex) can cause hippocampus neurocyte damage, excessive apoptosis, and dysfunction. Its initial reason is intracellular calcium overload in hippocampus triggered by N-methyl-D-aspartic acid receptor (NMDAR) over-activation. NMDAR activation can be suppressed by γ-aminobutyric acid (A) receptor (GABAAR). Whether GABAAR can prevent intense exercise-induced hippocampus apoptosis, damage, or dysfunction will be studied in this study.

METHODSAccording to dose test, rats were randomly divided into control (Con), Ex, muscimol (MUS, 0.1 mg/kg) and bicuculline (BIC, 0.5 mg/kg) groups, then all rats underwent once swimming Ex except ones in Con group only underwent training. Intracellular free calcium concentration ([Ca2+]i) was measured by Fura-2-acetoxymethyl ester; glial librillary acidic protein (GFAP) and synaptophysin (SYP) immunofluorescence were also performed; apoptosis were displayed by dUTP nick end labeling (TUNEL) stain; endoplasmic reticulum stress-induced apoptosis pathway was detected by Western blotting analysis; Morris water maze was used to detect learning ability and spatial memory.

RESULTSThe appropriate dose was 0.1 mg/kg for MUS and 0.5 mg/kg for BIC. Ex group showed significantly increased [Ca2+]i and astrogliosis; TUNEL positive cells and levels of GFAP, B cell lymphoma-2 (Bcl-2) associated X protein (Bax), caspase-3, caspase-12 cleavage, CCAAT/enhancer binding protein homologous protein (CHOP), and p-Jun amino-terminal kinase (p-JNK) in Ex group also raised significantly compared to Con group, while SYP, synapse plasticity, and Bcl-2 levels in Ex group were significantly lower than those in Con group. These indexes were back to normal in MUS group. BIC group had the highest levels of [Ca2+]i, astrogliosis, TUNEL positive cell, GFAP, Bax, caspase-3, caspase-12 cleavage, CHOP, and p-JNK, it also gained the lowest SYP, synapse plasticity, and Bcl-2 levels among all groups. Water maze test showed that Ex group had longer escape latency (EL) and less quadrant dwell time than Con group; all indexes between MUS and Con groups had no significant differences; BIC had the longest EL and least quadrant dwell time among all groups.

CONCLUSIONSActivation of GABAA R could prevent intense exercise-induced synapses damage, excessive apoptosis, and dysfunction of hippocampus.

Animals ; Apoptosis ; physiology ; Body Weight ; physiology ; Endoplasmic Reticulum Stress ; physiology ; Hippocampus ; metabolism ; Male ; Physical Exertion ; physiology ; Rats ; Rats, Sprague-Dawley ; Receptors, GABA ; genetics ; metabolism ; Synapses ; pathology

OBJECTIVETo evaluate the exercise-induced fatigue in operators during pesticide spraying based on surface electromyography (sEMC) signals and heart rate.

METHODSThe sEMG signals were recorded from the right trapezius, biceps brachii, extensor digitorum, and flexor digitorum of 19 operators by portable electromyography units during pesticide spraying using 3WS-16 manual sprayers. Meanwhile, the heart rate of operators was measured by the ambulatory blood pressure monitoring system. The changes in median frequency and heart rate were analyzed.

RESULTSPesticide spraying was defined as low-intensity labor. The median frequency of the right trapezius, biceps brachii, extensor digitorum, and flexor digitorum decreased significantly as pesticide spraying went on (P < 0.05). The body remained in a state of slight fatigue from 8 min after pesticide spraying began to the end of the operation.

CONCLUSIONThe degree of exercise-induced fatigue of operators can be evaluated based on sEMG signals and heart rate during pesticide spraying.

Arm ; Blood Pressure Monitoring, Ambulatory ; Electromyography ; Hand ; Heart Rate ; Humans ; Muscle Fatigue ; Muscle, Skeletal ; physiology ; Occupational Exposure ; adverse effects ; Pesticides ; Physical Exertion

INTRODUCTIONAccording to the findings of some studies, instability due to inertia during changes in speed may negatively impact the quality of chest compressions performed during cardiopulmonary resuscitation (CPR) in a moving environment. This study thus aimed to introduce a simple device that maintains the balance of a person performing CPR in a moving environment, such as an ambulance. We also sought to evaluate the effectiveness of this device in the improvement of the quality of chest compressions.

METHODSThe experiment comprised a total of 40 simulated cardiopulmonary arrest scenes (20 in the experimental group and 20 in the control), in which CPR was conducted by eight paramedics. Each simulation involved two paramedics randomly selected from the eight. The ambulance took the same route from the simulated site to the hospital, and continuous CPR was performed on a manikin in the ambulance with or without the aid of our proposed novel device.

RESULTSThe average number of chest compressions per simulation in the experimental and control groups was 1330.75 and 1266.60, respectively (p = 0.095). The percentage of chest compressions with adequate depth achieved in the experimental and control groups was 72% ± 4% and 50% ± 3%, respectively (p < 0.0001).

CONCLUSIONBy maintaining the balance of the CPR performer, our proposed novel device can offset the negative impact that instability (due to a moving environment) has on chest compressions. The device may also lead to an increase in the percentage of chest compressions that achieve adequate depth.

Adult ; Allied Health Personnel ; Ambulances ; Cardiopulmonary Resuscitation ; instrumentation ; methods ; Emergency Medical Services ; methods ; Equipment Design ; Equipment Safety ; Female ; Humans ; Male ; Manikins ; Movement ; Out-of-Hospital Cardiac Arrest ; mortality ; therapy ; Physical Exertion ; physiology ; Reference Values ; Risk Assessment ; Sensitivity and Specificity ; Survival Rate ; Treatment Outcome

Isokinetic technology in testing and training is the most advanced practical technique in the evaluation of muscle function. This method is a continuous dynamic test in the full range of the joint motion which has strong pertinence at the aspect of assessing muscle strength, and is an objective and quantitative method for reflecting each point's muscle strength in the range of the joint motion. This article reviews the key concepts, brief history of development and influencing factors of isokinetic technology in testing and training, introduces the progress in the field of rehabilitation medicine and sport science, etc., and discusses the future exploration in forensic science.
Biomechanical Phenomena ; Forensic Medicine/methods* ; Humans ; Isometric Contraction/physiology* ; Joints/physiopathology* ; Muscle Contraction/physiology* ; Muscle Strength/physiology* ; Muscle Strength Dynamometer ; Muscle, Skeletal/physiopathology* ; Physical Education and Training/methods* ; Physical Exertion ; Physical and Rehabilitation Medicine ; Posture ; Range of Motion, Articular/physiology* ; Sports Medicine ; Wounds and Injuries/rehabilitation*

Respirator breathing resistance impacts performance of wearers during constant work load. However, it is less clear as to how breathing resistance affects the tolerant capacity of users during graded work load. The present study investigated the tolerant capacity of 8 individuals during incremental work load. The 8 subjects were required to wear two matched respirators (respirators I and II which were designed to have different breathing resistances and the same dead space) respectively on separate days and then work to end points. Minute ventilation (V(E)), breathing frequency (BF), oxygen consumption (VO(2)) and heart rate (HR) were recorded during exercise, while tolerant time, response time and breathing discomfort were measured at the end of each test trial. The test variables were compared between the two respirators by using matched-pairs t-test. The results showed that the tolerant time was significantly reduced for the respirator I with higher level of breathing resistance when compared with its counterpart with lower breathing resistance (respirator II) (P<0.05). The same changes occurred for response time. Results also showed a significant increase in V(E) and BF for respirator I wearers when the work load was above 125 W. The O(2) consumption was similar under the two breathing resistance conditions. These findings suggested that the respiratory resistance caused by self-contained breathing apparatus (SCBA) has an impact on the tolerant capacity of users.
Airway Resistance ; physiology ; Exercise ; physiology ; Exercise Tolerance ; physiology ; Humans ; Male ; Oxygen Consumption ; physiology ; Physical Exertion ; physiology ; Respiration, Artificial ; methods ; Respiratory Mechanics ; physiology ; Young Adult

The present study was aimed to explore the changes of phosphorylated AMP-activated protein kinase (pAMPK) level in skeletal muscle after exposure to acute hypobaric hypoxia and exhaustive exercise. Thirty-two male Sprague-Dawley (SD) rats were randomly divided into sea level and high altitude groups. The rats in high altitude group were submitted to simulated 5 000 m of high altitude in a hypobaric chamber for 24 h, and sea level group was maintained at normal conditions. All the rats were subjected to exhaustive swimming exercise. The exhaustion time was recorded. Before and after the exercise, blood lactate and glycogen content in skeletal muscle were determined; AMPK and pAMPK levels in skeletal muscle were detected by Western blot. The results showed that the exhaustion time was significantly decreased after exposure to high altitude. At the moment of exhaustion, high altitude group had lower blood lactate concentration and higher surplus glycogen content in gastrocnemius compared with sea level group. Exhaustive exercise significantly increased the pAMPK/AMPK ratio in rat skeletal muscles from both sea level and high altitude groups. However, high altitude group showed lower pAMPK/AMPK ratio after exhaustion compared to sea level group. These results suggest that, after exposure to acute hypobaric hypoxia, the decrement in exercise capacity may not be due to running out of glycogen, accumulation of lactate or disturbance in energy status in skeletal muscle.
AMP-Activated Protein Kinases ; metabolism ; Altitude ; Animals ; Computer Simulation ; Glycogen ; metabolism ; Hypoxia ; physiopathology ; Lactic Acid ; blood ; Male ; Motor Activity ; physiology ; Muscle, Skeletal ; enzymology ; metabolism ; Phosphorylation ; Physical Exertion ; physiology ; Rats ; Rats, Sprague-Dawley

OBJECTIVETo assess the effect of oxidative stress in development of acute high altitude response (AHAR) during the process of strong physical work at high altitude and its change after return to lower altitude.

METHODSNinety-six officers and soldiers of rapid entering into high altitude (3 700 m) with strong physical work were analyzed, all subjects were male, aged 18-35 years. According to the symptomatic scores of AHAR were divided into 3 groups: severe AHAR (group A, n = 24), mild AHAR (group B, n = 47) and without AHAR (group C, n = 25). Levels in serum 8-iso prostaglandinF2alpha(8-iso-PGF2alpha), superoxide dismutase (SOD) and malonaldehyde (MDA) were measured at higher altitude stayed 50 d and after return to lower altitude (1 500 m) 12 h and 15 d, and 50 healthy volunteers (group D) at 1 500 m altitude served as controll.

RESULTSLevels of serum 8-iso-PGF2alpha and MDA [(9.53 +/- 0.47) microg/L, (8.91 +/- 0.39) micromol/L] were significantly higher in group A than those in group B [(8.34 +/- 0.42) microg/L, (7.31 +/- 0.32) micromol/L] , group C [(7.02 +/- 0.48) microg/L, (6.41 +/- 0.23) micromol/L] and group D [(5.13 +/- 0.56) microg/L, (5.48 +/- 0.33) micromol/L], (all P < 0.01), and serum SOD [(52.08 +/- 3.44) micro/ml] was significantly lower in group A than that in group B [62.27 +/- 2.54) micro/ml], group C [(71.99 +/- 3.35) micro/ml] and group D [(80.78 +/- 3.44) micro/ ml] (all P < 0.01), there were significant differences between group B and C, C and D (all P < 0.01). At altitude 3 700 m 50 d, AHAR scores was positively correlated with serum 8-iso-PGF2alpha and MDA (all P < 0.01), negatively correlated with SOD (P < 0.01). Serum 8-iso-PGF2alpha and MDA were negatively correlated with SOD (all P < 0.01). Levels of serum 8-iso-PGF2alpha and MDA were significantly higher at altitude of 3 700 m 50 d than those at altitude of 1 500 m 12 h,15 d in group D (all P < 0.01), and serum SOD was significantly lower than that at 1 500 m 12 h,15 d in group D (all P < 0.01), there were significantly difference between at 1 500 m 12 h and 15 d (all P < 0.01), there were no difference between at 15 d in group D (all P > 0.05).

CONCLUSIONThe more serious of oxidative stress and oxidative/antioxidative imbalance, the more serious of AHAR, oxidative stress and oxidative/antioxidative imbalance may be involved in the development of AHAR. The changes were obviously improved after return to lower altitude 12 h, and recovered to normal after 15 d.

Adolescent ; Adult ; Altitude ; Altitude Sickness ; physiopathology ; Humans ; Male ; Oxidative Stress ; physiology ; Physical Exertion ; physiology ; Young Adult

OBJECTIVETo observe the effect of Chinese herbal compound on variance of neurotransmitters in rat telencephalon and to further discuss the mechanism underlying Chinese herbal compound in improving exercise capacity and promoting recovery from exercise-induced fatigue.

METHODS64 rats (8 week old) were randomly divided into medicine group (MG) and control group (CG). Chinese herbal compound was administered to rats of MG for 8 weeks. 8 weeks later, every group was divided into 4 subgroups and all were killed at different time point separately, and then neurotransmitter in rat brain was tested.

RESULTSThe exhaustion time of MG was significantly longer than that in CG (P < 0.01). In rest conditions, glutamic acid (GLU) of MG was significantly higher than that in CG (P < 0.01), while, there were no significant differences between MG and CG in other indexes. After fixed quantitative load exercise, the content of 5-hydroxytryptamineZZ(5-HT), 5-hydroindole acetic (5-HIAA), gamma-aminobutyric acid (GABA), Dopamine (DA) and 5-HT/5-HIAA were significantly lower than those in CG, while, GLU, GLU/GABA and DA/5-HT were significantly higher than those in CG. Compared with CG, exhaustion significantly (P < 0.05) decreased 5-HT, GABA and 5-HT/5-HIAA, and significantly (P<0.05) increased GLU, DA/5-HT and GLU/GABA level in MG. 12 h after exhaustion, in contrast to CG, level of 5-HT and 5-HT/5-HIAA in MG were significantly (P < 0.01) lower while GLU, DA, GABA and DA/5-HT were significantly (P < 0.01) higher.

CONCLUSIONDuring exhaustion exercise, Chinese herbal compound demonstrated strong inhibiting effect on synthesis of 5-HT, 5-HIAA, DA, GABA and promoting effect on GLU synthesis, this had been confirmed by the combined effect, including increase of excitatory transmitter and excitability of central nervous system and the prolongation of exhaustion time and promoting recovery from fatigue.

Amino Acids ; metabolism ; Animals ; Biogenic Monoamines ; metabolism ; Drugs, Chinese Herbal ; pharmacology ; Fatigue ; metabolism ; physiopathology ; Hydroxyindoleacetic Acid ; metabolism ; Male ; Neurons ; metabolism ; Physical Conditioning, Animal ; physiology ; Physical Exertion ; physiology ; Rats ; Rats, Wistar ; Serotonin ; metabolism ; Telencephalon ; drug effects ; metabolism

OBJECTIVETo study the dynamic characteristics of serotonin (5-HT), dopamine (DA) and their metabolin changes in brain during the development of exercise-induced central fatigue.

METHODSCoupling of microdialysis and capillary electrophoresis-laser induced fluorescence detection method were used to continuously monitored the changes of DA, tryptophan (Trp), tyrosine (Tyr), 5-HT and 5-hydroxyindoleacetic acid (5-HIAA) in striatum extracellular fluid during the exhaustive exercise and recovery time.

RESULTSThe concentrations of Trp, 5-HT, 5-HIAA in striatum extracellular fluid had no remarkable changes in the early time of exercise (P < 0.05), while they significantly increased during the later time of exercise and whole recovery time (P < 0.05, P < 0.01). The concentrations of DA and Tyr significantly increased over basal level in the later exercise time, exhaust and recovery time (P < 0.05, P < 0.01). DA/5-HT significantly increased in the initial time of exercise (P < 0.05, P < 0.01), while decreased during the later exercise time, the nadir occurred at 15 minutes before rats exhausted. DA/5-HT slightly recovered back to basal level during the recovery time, and there was no significant difference during later exercise, exhausted and recovery time compared with basal level (P < 0.05).

CONCLUSIONThe changes of DA and 5-HT in striatum have phase characteristics. Both of them significantly increase during the development of exercise-induced fatigue. However, the 5-HT plays the dominant role in the dynamic changes of them.

Animals ; Corpus Striatum ; metabolism ; Dopamine ; metabolism ; Fatigue ; metabolism ; physiopathology ; Male ; Physical Conditioning, Animal ; physiology ; Physical Exertion ; physiology ; Rats ; Rats, Wistar ; Serotonin ; metabolism

OBJECTIVETo observe the modulatory effect of subthalamic nucleus (STN) on activity of motor cortex during exhausting exercise.

METHODSElectrocorticogram (ECoG) and local field potentials (LFPs) recording techniques were applied simultaneously to observe the dynamic changes of oscillations in sensorimotor area and STN of rat during exhausting exercise.

RESULTSRats ran well initiatively with treadmill at the beginning of the exercise, about 45 min (45 +/- 11.5) later, movement capacity reduced. Corresponding electrical property showed that STN activity increased significantly while activity of cortex decreased significantly. Subsequently rats continued exercise with minor external stimulation utill exhaustion. Activity of ECoG reached the minimum under exhausting stations (P < 0.01), while the activity of LFPs changed insignificantly (P > 0.05).

CONCLUSIONDuring the exhausting exercise, the cortex activity was extensively depressed with the development of fatigue, while the activity of STN increased significantly at the early stage of fatigue, STN took part in the modulation of central fatigue through negative induction. And the increase of STN activity may be one of the key measures accounting for protective inhibition.

Animals ; Cerebral Cortex ; physiology ; Electrophysiological Phenomena ; physiology ; Male ; Neurons ; physiology ; Physical Conditioning, Animal ; physiology ; Physical Exertion ; physiology ; Rats ; Rats, Wistar ; Subthalamic Nucleus ; physiology