فهرست مطالب

Sports Medicine - Volume:8 Issue: 3, Sep 2017

Asian Journal of Sports Medicine
Volume:8 Issue: 3, Sep 2017

  • تاریخ انتشار: 1396/07/20
  • تعداد عناوین: 8
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  • Pietro Picerno * Page 1
    The mathematical relationship between the force and the velocity as determined during isoinertial progressive resistance strength tests is being extensively used for the assessment of neuromuscular qualities and for a targeted resistance training. The reliability of this relationship depends on the reliability of the collected force and velocity values. This reliability can be jeopardized by several factors such as: 1) an erroneous movement execution; 2) an improper load assignment; 3) a useless number of performed repetitions; 4) an inadequate rest interval between sets of repetitions; 5) an improper use of the measurement device and of the relevant computing methods. The aim of this contribution is to provide the operator with a list of good practice rules retrieved from the specific scientific literature concerning the instrumented assessment of muscle strength during isoinertial resistance exercises.
    Keywords: Strength Testing, Isoinertial, Force, Velocity, Best Practice
  • Khadijeh Irandoust, Morteza Taheri * Page 2
    Objective
    Since the rate of depression and Vitamin D deficiency has been reported in Iranian obese women, it needs to be considered seriously by researchers. Therefore, the aim of this research was to investigate the effect of vitamin D supplement (VD) and indoor physical activity (IPA) vs outdoor physical activity (OPA) on the depression of obese depressed women.
    Methods
    This was a prospective study with 75 women (mean age: 43.5 ± 12.8 years, with body mass index (BMI) ranging from 30.0 to 35.0 kg/m2). They were randomly assigned into four experimental groups who either did indoor or outdoor physical activity with or without Vitamin D. Depressive symptoms were assessed with the Beck depression inventory. The intervention group (indoor and outdoor physical activity with vitamin D) was administered a 2,000 IU Vitamin D per day for 12 weeks. The training program included warming-up, main protocol (treadmill versus outdoor jogging) and cooling-down four times a week for 3 months.
    Results
    The results indicated that the level of depression in OPA VD group was improved from severe (33.26 ± 2.12) to mild (16.73 ± 1.38) suggesting 50% improvement in depression score (P = 0.001) and there was, also, a significant improvement in the depression level of IPA, OPA, and IPA groups from sever to moderate level in depression scores (P = 0.001).
    Conclusions
    Both vitamin D and exercise (especially outdoor) have positive effects on depressive symptoms of depressed obese women. As a result, promotion of an active outdoor lifestyle and having sufficient Vitamin can counteract vitamin D deficiency and the rate of depression in this vulnerable population.
    Keywords: Vitamin D, Indoor, Outdoor, Depression
  • Eliane Cristina De Andrade Goncalves, Heloyse Elaine Gimenes Nunes, Diego Augusto Santos Silva * Page 3
    Background
    The relationship between maximum consumption of oxygen and indicators of body composition is important due in increasing the chance of developing cardiovascular risk factors. Therefore, the aim of this study was to investigate the association between body fat anthropometric indicators (BMI, WC, WHtR, CI, triceps skinfold, subscapular skinfold, suprailiac skinfold) with VO2max and estimate the predictive ability of anthropometric indicators for the VO2max variation in adolescents.
    Methods
    The study included 879 adolescents (14 - 19 years) and was carried out in southern Brazil. Aerobic fitness was assessed by the modified Canadian Aerobic Fitness test (mCAFT). Independent variables were: body mass index, waist circumference, waist /height ratio, conicity index (CI), triceps skinfold, subscapular skinfold, suprailiac skinfold, sum of triceps and subscapular skinfolds and sum of triceps, subscapularis and suprailiac skinfolds. Analyses were controlled for sociodemographic variables, physical activity and sexual maturation.
    Results
    With the exception of CI for girls, all anthropometric indicators were associated with VO2max of adolescents in both sexes (P
    Conclusions
    Only CI for girls did not explain the VO2max variation in adolescents, and the sum of the three skinfolds was the indicator that best predicted the VO2max variation in adolescents.
    Keywords: Association, Overweight, Lifestyle, Exercise, Adolescent Health
  • Thomas Dillern * Page 4
    Objectives
    The aerobic energy-delivery system substantially contributes to energy consumption while playing soccer. Fatigue and recovery in soccer are hence closely related to this system’s efficiency, however research emphasizing this relationship is lacking. This study aimed at examining if it is possible to detect post-match fatigue and recovery in soccer players by exploring markers (e.g. oxygen consumption, heart rate, and blood lactate) of the aerobic energy-delivery system’s efficiency during a steady-state running test in the laboratory.
    Methods
    Seventeen well-trained male soccer players (age of 21.94 (± 3.5) years, body mass of 77.95 (± 6.76) kg, and a stature of 180.2 (± 5.98)) completed a repeated measures analysis where a sub-maximal steady-state running test was performed 3 times; a rested condition (pre-match test) served as baseline values, immediately after match (post-match test) served as the rate of fatigue, and 24 hours later (24-hour post-match test) served as the state of recovery.
    Results
    The one-way repeated measures analysis of variance (ANOVA) revealed significant effect (P ≤ 0.01) on all variables (body mass, oxygen consumption, heart rate, respiratory exchange ratio, blood lactate, and rating of perceived exertion). Multivariate partial eta squared analysis further indicated that this effect for all variables was interpreted as a very large effect size (R ≥ 0.47). Regarding pairwise comparison, all variables in the post-match test differed (P ≤ 0.05) to the pre-match test. In the example, oxygen consumption increased from pre-match to post-match from 175.59 to 183.02 (mL.kg-0.25·min-1). Concerning the 24-hour post-match test, heart rate and blood lactate was found to be significantly different (P ≤ 0.05) compared to the pre-match test. The remaining variables were however, at this point, about to be re-established to their pre-match values.
    Conclusions
    In this study, markers of aerobic energy-delivering system were proved functional in detecting post-match fatigue and recovery in soccer players.
    Keywords: Aerobic Performance Ability, Fatigue, Recovery, Soccer, Laboratory Testing
  • Pantelis Theodoros Nikolaidis *, Filipe Manuel Clemente, Krzysztof Busko, Beat Knechtle Page 5
    Previous research has well described the acute responses of the human body to boxing; nevertheless, less data exist about the effect of recovery modes differing for body position during breaks on these responses. Therefore, the aim of the present study was to examine the impact of two modes of break (sitting versus standing) on heart rate (HR), rate of perceived exertion (RPE), countermovement jump (CMJ) and handgrip muscle strength (HGS) in a simulated boxing combat of three 3-min rounds with 1-min breaks. Participants were male boxers (n = 15) with age, body mass, body height, body mass index and training experience of 21.4 (6.3) yrs, 67.7 (10.0) kg, 172 (6) cm, 22.9 (4.2) kg.m-2 and 2.9 (1.9) yrs, respectively. Mean HR was recorded through all rounds and breaks. Immediately after each round, participants were questioned for RPE (6 - 20 Borg scale). CMJ and HGS were measured before and after combat. A mixed analysis of variance found no time × body position interaction on variables (P > 0.05). However, the p value almost reached statistical significance (P = 0.062, η2 = 0.426) in the case of RPE, that was, compared to the sitting position, a trend of increased RPE for the standing position across time was observed. A main effect of time on HR, RPE and CMJ was shown (P
    Keywords: Countermovement Jump, Handgrip Strength, Heart Rate, match analysis, Rate of Perceived Exertion
  • Ladan Zakeri, Ali Asghar Jamebozorgi, Amir Hossein Kahlaee * Page 6
    Background
    The gold standard for postural stability evaluation is the force platform; which has multiple limitations such as high costs, not being portable and being difficult to implement. Simple balance training devices have been recently tried to take this role. The validity and reliability of such devices have been a major concern.
    Methods
    Twenty symptom-free university students volunteered to take part in this methodological study. The center of pressure, anterior-posterior displacement range and total path length were measured during static standing tasks under four conditions of eyes opened and closed with firm and foam support surface by Bertec force platform and Wii Balance Board. Intra-class correlation coefficient and standard error of measurement were used to assess relative and absolute reliability, respectively. The mean differences of the measurements of the two devices were compared to zero by one sample t-test to check the construct validity of the Wii Balance Board. Bland and Altman plots were also used for descriptive evaluation of the mean and the variability of measurement differences of the two devices. Regression analysis was used to check if there was any systematic bias between the mean values and the differences between the two devices.
    Results
    All center of pressure measures from both devices showed statistically significant relative reliability (P 0.05). Regression analysis of the pooled mean scores and the measurement differences revealed no significant systematic bias between them (P > 0.05).
    Conclusions
    Both Bertec force platform and Wii Balance Board devices showed acceptable reliability. While the center of pressure driven variables measured by the two devices are comparable, there is a trend toward overestimation of these variables by the Wii Balance Board. The difference between the measurements of the two devices was found to be highly variable without any significant systematic bias.
    Keywords: Wii Balance Board, Force Platform, Center of Pressure, Reliability, Validity
  • Ali Yalfani, Frazaneh Gandomi *, Masomeh Kohboomi Page 7
    Background
    Previous studies have reported that athletes with chronic ankle instability have altered gluteal muscles activation; however: there has not been an investigation that study the effect of hip musculature fatigue on ankle functional performance.
    Objectives
    The purpose of this study was to study the effect of gluteal muscles fatigue on functional performance testing and balance in athletes with and without chronic ankle instability.
    Methods
    In this semiexperimental study, we recruited 24 physically active participants. We separated the participants into 2 groups: 12 female with chronic ankle instability (CAI) and 12 control subjects. We applied gluteal muscles fatigue protocol and immediately after that functional performance tests were measured.
    Results
    Our results showed that, the difference in the scores of figure 8 tests was significant but there were no significant differences between groups. Also, scores of side hop test were significantly different after fatigue, and significant differences existed between groups. 6-meters cross test had similar results to figure 8, and the square test had similar results to side hop test. The difference in results of Romberg test scores for assessment of static balance and Y-test scores for assessment of dynamic balance were significant in after fatigue protocol, with no significant differences between groups.
    Conclusions
    The results showed that hip muscles fatigue increased the time of all functional performance tests, but two test scores had significant differences between groups, so gluteal fatigue should be considered as a risk factor for recurrent ankle sprains.
    Keywords: Hip Muscles, Postural Balance, Ankle Instability
  • Eduardo Marcel Fernandes Nascimento, Maria Augusta Pedutti Dal Molin Kiss, Tony Meireles Santos, Mike Lambert, Flavio Oliveira Pires* Page 8
    Background
    Heart rate variability (HRV) data set has been used to identify HRV thresholds during exercise. However, the relationship between HRV thresholds and the first (LT1) and second lactate threshold (LT2), has been poorly investigated during maximal running test. In this regard, HRV may act as a useful, less expensive and time consuming method to estimate physiological thresholds.
    Objectives
    The aim of the present study was to verify the validity and reproducibility of the heart rate variability (HRV) method to determine first and second lactate thresholds during a maximal running test.
    Methods
    Nineteen male runners (30.4 ± 4.1 years; body mass of 74.3 ± 8.5 kg; height of 176 ± 6.4 cm and body fat of 13.8 ± 4.6 %) performed two progressive maximal tests on a treadmill, with initial speed at 5 km.h-1 and 1 km.h-1 increments every 3 minutes, until exhaustion. Measures of HRV and blood lactate concentrations were obtained during the tests and physiological thresholds were identified as lactate thresholds by using fixed concentrations (2.0 and 3.5 mmol.L-1) and Dmax method, as well as HRV thresholds.
    Results
    There were no differences between the first physiological thresholds identified as lactate (2.0 mmol.L-1 = 11.9 ± 2.9 km.h-1 and Dmax = 12.3 ± 1.5 km.h-1) or HRV threshold (11.6 ± 1.6 km.h-1). Accordingly, there were no differences between the second physiological thresholds identified as lactate threshold (3.5 mmol.L-1 = 14.2 ± 2.6 km.h-1) or HRV threshold (14.2 ± 2.0 km.h-1). Furthermore, HRV thresholds showed good agreement between test and retest.
    Conclusions
    Physiological thresholds identified by using HVR data set provided reliable and practical estimation of LT1 and LT2 during a maximal running test.
    Keywords: Heart Rate Variability, Blood Lactate Concentrations, Autonomic Modulation