The Effect of Electrical Stimulation on Blood Lactate after Anaerobic Muscle Fatigue Induced in Taekwondo Athletes

Effect of active recovery using individual maximum exercise capacity: a pilot study

[Purpose] The intensity of active recovery (AR) for performance recovery is often determined using breath gas analyzers and other special equipment. However, such procedures are difficult to perform in the field or where facilities are inadequate. Although several AR methods using simple patient-derived information have been proposed, only a few have specifically addressed their immediate effects. The present study aimed to quantify the immediate effects of AR, which was determined using the maximum exercise capacity calculated using a physical fitness test without specialized devices. [Participants and Methods] Thirty-two healthy male participants were equally divided into AR and control groups. Each group performed squat jumps, followed by a recovery intervention of jogging at a set intensity in the AR group or rest in a seated position in the control group. Standing long jumps performed before and after the squat jumps as well as after the intervention were analyzed. [Results] The recovery rate for standing long jumps was significantly higher in the AR group than in the control group. [Conclusion] The results of this pilot study indicate that the implementation of AR based on maximum exercise capacity may enhance performance recovery and requires further validation in larger studies.

Electric Muscle Stimulation (EMS) Does Not Improve Anaerobic Performance Measures During a Repeated Wingate Test

Introduction: The aim of this study was to examine differences between a control warm-up and an Electric Muscle Stimulation (EMS)-induced warm-up in off-road cyclists when examining anaerobic performance measures from a repeated Wingate test (WAnT). Methods: Twelve trained off-road cyclists completed a randomized crossover study (age: 31 ± 10 years, height: 176.79 ± 6.09 cm, body mass: 74.57 ± 4.77 kg). Participants completed two randomized, separate testing sessions involving a control warm-up and an EMS warm-up before undergoing the repeated WAnT, which was used to collect anaerobic performance and physiolo- gical measures during both sessions. High-frequency EMS was applied to the knee extensor muscles for 4 min after a standardized warm-up during the EMS session. Results: Analysis revealed that there were no significant differences between mean power output, peak power output, and percentage decrement between the two sessions. The EMS session resulted in significantly lower average HR values and significantly lower differences in pre-to-post-test blood lactate values when compared to the control session. Discussion: According to the results of this study, an acute application of EMS is not a useful tool for off-road cyclists to improve power output or maintain anaerobic capacity. Hence, its use before competition is questionable.

Changes in Hippocampus and Amygdala Volume with Hypoxic Stress Related to Cardiorespiratory Fitness under a High-Altitude Environment

The morphology of the hippocampus and amygdala can be significantly affected by a long-term hypoxia-induced inflammatory response. Cardiorespiratory fitness (CRF) has a significant effect on the neuroplasticity of the hippocampus and amygdala by countering inflammation. However, the role of CRF is still largely unclear at high altitudes. Here, we investigated brain limbic volumes in participants who had experienced long-term hypoxia exposure in Tibet (3680 m), utilizing high-resolution structural images to allow the segmentation of the hippocampus and amygdala into their constituent substructures. We recruited a total of 48 participants (48 males; aged = 20.92 ± 1.03 years) to undergo a structural 3T MRI, and the levels of maximal oxygen uptake (VO_2max) were measured using a cardiorespiratory function test. Inflammatory biomarkers were also collected. The participants were divided into two groups according to the levels of median VO_2max, and the analysis showed that the morphological indexes of subfields of the hippocampus and amygdala of the lower CRF group were decreased when compared with the higher CRF group. Furthermore, the multiple linear regression analysis showed that there was a higher association with inflammatory factors in the lower CRF group than that in the higher CRF group. This study suggested a significant association of CRF with hippocampus and amygdala volume, which may be related to hypoxic stress in high-altitude environments. A better CRF reduced physiological stress and a decrease in the inflammatory response was observed, which may be related to the increased oxygen transport capacity of the body.

Relationship between skeletal muscle mass and blood lactate level reduction after short squat jumps in healthy adult non-athletes

[Purpose] Blood lactate reduction helps in understanding muscle recovery. Although light exercise and stretching are known interventions to reduce its concentration, the impact of skeletal muscle mass on blood lactate clearance is unknown. This study aimed to determine the relationships between blood lactate reduction and skeletal muscle mass following exercise. [Participants and Methods] Healthy non-athletic males performed squat jumps for 1 minute and 30 seconds. Blood lactate level was measured before and immediately after the exercise and then every 2 minutes for a period of 20 minutes. The decrease in blood lactate level was estimated as the difference between the minimum and maximum values. The rate of decrease was calculated by dividing the decrease in blood lactate level by time. Blood lactate level was measured using Lactate ProTM 2, while skeletal muscle mass was assessed using InBody 430. [Results] There was a significant positive correlation between skeletal muscle mass, the amount of blood lactate level reduction, and the rate of reduction of blood lactate level. [Conclusion] Our results demonstrated that greater skeletal muscle mass enabled a greater decrease in blood lactate level, suggesting that skeletal muscle mass may be involved in the reduction of blood lactate level after a squat jump. Interventions to increase skeletal muscle mass may promote more efficient lactate metabolism and muscle fatigue recovery.

SPECT/CT with 99mTc-sestamibi for the evaluation of skeletal muscle perfusion after electrical muscle stimulation in athletes

Objective

The purpose of this study was to evaluate the effects of electrical muscle stimulation (EMS) on muscles, using ^99mTc-sestamibi SPECT/CT.

Materials and Methods

We prospectively enrolled 20 consecutive male professional water polo players. The mean age was 25 years (range, 18-36 years). All athletes underwent ^99mTc-sestamibi SPECT/CT of the thigh (rectus femoris and vastus medialis muscle groups) before and after EMS. Images were quantified to identify increases in perfusion after EMS.

Results

Before EMS, there were no significant differences between the right and left thigh (rectus femoris and vastus medialis muscles) in terms of perfusion (p = 0.4). However, the comparison between the pre- and post-EMS analyses of the same muscle groups showed significant differences in radiotracer uptake (p < 0.001), with a mean increase in perfusion of 128% for the rectus femoris muscle group (95% CI: 0.86-1.61) and 118% for the vastus medialis muscle group (95% CI: 0.96-1.79).

Conclusion

^99mTc-sestamibi SPECT/CT is an objective means of evaluating blood flow in muscles submitted to EMS, which appears to promote significant increases in such blood flow.

Monitoring of pre-competition dehydration- induced skeletal muscle damage and inflammation levels among elite wrestlers

BACKGROUND

Weight loss practice before competitions is a common method in weight sports.

OBJECTIVE

The current study aimed to monitor Plasma Osmolarity (POsm), skeletal muscle damage and inflammation levels induced by pre-competition dehydration among elite wrestlers.

METHODS

Twenty-four male elite wrestlers participated in the study. A survey information form that assessed pre-competition weight loss practices were administered to the wrestlers. Additionally, Total Creatine Kinase (CK), Lactate Dehydrogenase (LDH), Aspartate Aminotransferase (AST), Alanine Aminotransferase (ALT), C-reactive Protein (C-RP) and POsm, analyses were evaluated by a specialist at the biochemical laboratory. POsm level for euhydration is ⩽ 290 mOsm/L. But if POsm level is > 290, then dehydration occurs. The wrestlers were divided into two groups according to POsm levels as weight loss and non-weight loss group.

RESULTS

There were differences in the pre and post-test POsm levels of weight loss group. Similarly; it was identified that there were also statistically significant differences in terms of ALT, LDH and CK levels of weight loss group between pre and post-test.

CONCLUSIONS

It was seen that POsm and levels of all indicators of skeletal muscle damage were higher than non-weight loss group. However, it was found that there were not any differences in terms of C-RP levels.

Effects of habitual smoking on cardiopulmonary function in taekwondo athletes

This study aimed to verify habitual smoking effects on cardiopulmonary function in taekwondo athletes. Subjects were university taekwondo athletes aged 20-24 years in nonsmoker (n= 9) and smoker (n= 6) groups. Subjects underwent an exercise examination for their ventilation threshold, minute ventilation, oxygen uptake, maximum volume of minute oxygen consumption, heart rate, and oxygen pulse during exercise and 1, 3, and 5 min after maximum exercise. The time of reaching the ventilation threshold was significantly higher in nonsmokers than in smokers. Heart rate during recovery after maximum exercise was significantly lower in nonsmokers for 1 and 3 min. Nonsmokers had significantly higher time for reaching the ventilation threshold and heart rate recovery at 1 and 3 min after exercise. The higher timing of accumulation fatigue in ventilation amount and faster recovery after exercise are useful in continuous exercise and improving athletic performance. Thus, athletes should stop smoking as soon as possible to improve their aerobic physical fitness and athletic performance.

Influence of preliminary exercise training on muscle damage indices in rats after one bout of prolonged treadmill exercise

[Purpose] The purpose of this study was to investigate the effects of exercise on muscle damage indices in male Sprague-Dawley rats. Two groups of rats were trained in either moderate- or high-intensity treadmill running for 4 weeks. Subsequently, the concentrations of creatine kinase, lactate dehydrogenase, and high-sensitivity C-reactive protein were examined following a single bout of prolonged (3-h) intensive exercise. [Subjects and Methods] The study included forty 6-week-old male Sprague-Dawley rats weighing 150–180 g each. The aerobic exercise group was divided into high-intensity (28 m/min) and moderate-intensity (15 m/min) subgroups. Both subgroups were trained for 35 min daily for 6 days per week (excluding Sunday) over a 4-week period. Following training, the high- and moderate-intensity exercise groups and a non-exercise group performed one bout of prolonged (3-h) treadmill exercise for 3 hours at a speed of 15 m/min. [Results] Creatine kinase and lactate dehydrogenase levels differed significantly among the groups. [Conclusion] The preliminary exercise groups showed lower muscle damage and inflammatory response levels than the non-exercise group after the bout of prolonged intensive exercise.

Analysis of injury types for mixed martial arts athletes

[Purpose] The purpose of the present study was to examine the types of injuries associated with mixed martial arts and their location in order to provide substantial information to help reduce the risk of these injuries during mixed martial arts. [Subjects and Methods] Data were collected from 455 mixed martial arts athletes who practiced mixed martial arts or who participated in mixed martial arts competitions in the Seoul Metropolitan City and Gyeongnam Province of Korea between June 3, 2015, and November 6, 2015. Questionnaires were used to collect the data. The convenience sampling method was used, based on the non-probability sampling extraction method. [Results] The arm, neck, and head were the most frequent locations of the injuries; and lacerations, concussions, and contusions were the most frequently diagnosed types of injuries in the mixed martial arts athletes in this study. [Conclusion] Reducing the risk of injury by establishing an alert system and preventing critical injuries by incorporating safety measures are important.

Dehydration, skeletal muscle damage and inflammation before the competitions among the elite wrestlers

[Purpose] The present study aimed to identify weight-loss and hydration levels before competitions among elite wrestlers and determine the skeletal muscle damage and inflammation levels after dehydration. [Subjects] Seventy-two elite wrestlers who participated in the Turkish Wrestling Championship. [Methods] With the help of specialists, 5 cc of blood were drawn from the forearm veins of the wrestlers. Laboratory analyses of Na(+), BUN, Glucose, CK, LDH, AST, ALT, C-RP levels were performed. Using a mathematical formula for hydration the POsm levels of the athletes were calculated. [Results] The wrestlers were divided into two groups based on hydration status. There were significant correlations between hydration indicators of Na(+), BUN and PBWL values. There were significant differences between AST, LDH, CK values and skeletal muscle damage indicators of the two groups, but there were no significant differences between the inflammation levels and C-RP values of the groups. [Conclusion] No differences existed in inflammation levels among the wrestlers, although dehydrated wrestlers suffered from higher level of skeletal muscle damage than wrestlers who were not dehydrated.

Effects of self-selected dehydration and meaningful rehydration on anaerobic power and heart rate recovery of elite wrestlers

[Purpose] This study aimed to verify the effects of self-directed weight loss on lower- and upper-body power, fatigue index, and heart rate recovery immediately before a meaningful competition (12 hours of recovery). In addition, this study tested the hypothesis that weight loss provides advantages in strength and power, as the relative power of the wrestlers is higher than that of opponents in the same weight class who do not reduce weight. [Subjects and Methods] Eleven well-trained wrestlers volunteered for the study. At baseline, their mean ± SD age, body mass, and height were 20.45 ± 2.69 years, 74.36 ± 9.22 kg, and 177 ± 5.71 cm, respectively. Repeated-measures one-way analysis of variance was performed to analyze differences. [Results] Rapid weight loss achieved by restriction of energy and fluid intake resulted in exercise-impaired decreases in peak power and increased fatigue index. Moreover, weight loss by dehydration negatively affected cardiovascular stability. [Conclusion] Most of the negative effects of rapid weight loss disappear after a 12-hour recovery period, and relative peak power increases after weight loss.

Neuromuscular Electrical Stimulation: No Enhancement of Recovery From Maximal Exercise

Purpose:

To investigate the use of neuromuscular electrical stimulation (NMES) during acute recovery between 2 bouts of maximal aerobic exercise.

Methods:

On 3 separate days, 19 trained male cyclists (28 ± 7 y, 76.4 ± 10.4 kg, power output at maximal aerobic power [pVo2max] 417 ± 44 W) performed a 3-min maximal cycling bout at 105%PVo2maxbefore a 30-min randomly assigned recovery intervention of passive (PAS: resting), active (ACT: 30%PVo2max), or NMES (5 Hz, 4 pulses at 500 μs). Immediately afterward, a cycle bout at 95%PVo2maxto exhaustion (TLIM) was performed. Heart rate (HR) and blood lactate (BLa) were recorded at designated time points. Data were analyzed using repeated-measures ANOVA with a Tukey honestly significantly different post hoc test. Statistical significance threshold wasP< .05.

Results:

The TLIMwas significantly shorter for NMES than for ACT (199.6 ± 69.4 s vs 250.7 ± 105.5 s:P= .016) but not PAS recovery (199.6 ± 69.4 s vs 216.4 ± 77.5 s:P= .157). The TLIMwas not significantly different between ACT and PAS (250.7 ± 105.5 s vs 216.4 ± 77.5 s:P= .088). The decline in BLa was significantly greater during ACT than NMES and PAS recovery (P< .001), with no difference between NMES and PAS. In addition, HR was significantly higher during ACT than NMES and PAS recovery (P< .001), with no difference between NMES and PAS.

Conclusions:

NMES was less effective than ACT and comparable to PAS recovery when used between 2 bouts of maximal aerobic exercise in trained male cyclists.

Influence of taekwondo as security martial arts training on anaerobic threshold, cardiorespiratory fitness, and blood lactate recovery

[Purpose] This study was conducted to determine the influence of Taekwondo as security martial arts training on anaerobic threshold, cardiorespiratory fitness, and blood lactate recovery. [Subjects and Methods] Fourteen healthy university students were recruited and divided into an exercise group and a control group (n = 7 in each group). The subjects who participated in the experiment were subjected to an exercise loading test in which anaerobic threshold, value of ventilation, oxygen uptake, maximal oxygen uptake, heart rate, and maximal values of ventilation / heart rate were measured during the exercise, immediately after maximum exercise loading, and at 1, 3, 5, 10, and 15 min of recovery. [Results] At the anaerobic threshold time point, the exercise group showed a significantly longer time to reach anaerobic threshold. The exercise group showed significantly higher values for the time to reach VO_2max, maximal values of ventilation, maximal oxygen uptake and maximal values of ventilation / heart rate. Significant changes were observed in the value of ventilation volumes at the 1- and 5-min recovery time points within the exercise group; oxygen uptake and maximal oxygen uptake were significantly different at the 5- and 10-min time points; heart rate was significantly different at the 1- and 3-min time points; and maximal values of ventilation / heart rate was significantly different at the 5-min time point. The exercise group showed significant decreases in blood lactate levels at the 15- and 30-min recovery time points. [Conclusion] The study results revealed that Taekwondo as a security martial arts training increases the maximal oxygen uptake and anaerobic threshold and accelerates an individual’s recovery to the normal state of cardiorespiratory fitness and blood lactate level. These results are expected to contribute to the execution of more effective security services in emergencies in which violence can occur.