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Tikkanen O.,University of Jyvaskyla | Tikkanen O.,Mega Electronics Ltd | Tikkanen O.,Pajulahti Sports Center | Hu M.,University of Jyvaskyla | And 5 more authors.
Physiological Measurement | Year: 2012

The present study examined whether shorts with textile electromyographic (EMG) electrodes can be used to detect second ventilatory threshold (V T2) during incremental treadmill running. Thirteen recreationally active (REC) and eight endurance athletes were measured for EMG, heart rate, blood lactate and respiratory gases during VO 2maxtest (3 min ramps, 1 kmh 1increments). V T2, onset of blood lactate accumulation (OBLA) and EMG threshold (EMG T) were determined. In athletes, OBLA occurred at 56 6 mLkg 1min 1, V T2occurred at 59 6 mLkg 1min 1, and EMG T at 62 6 mLkg 1min 1without significant differences between methods (analysis of variance: ANOVA). In REC participants, OBLA occurred at 40 10 mLkg 1min 1, V T 2occurred at 43 7 mLkg 1min 1, and EMG T at 41 9 mLkg 1min 1without significant differences between methods (ANOVA). For the entire group, correlation between EMG T and V T2was 0.86 (P < 0.001) and 0.84 (P < 0.001) between EMG T and OBLA. Limits of agreement between EMG T and V T2were narrower in athletes than in REC participants. Thus, it is concluded that estimation of V T 2using EMG T in athletes is more valid than in REC participants. In practice, experienced runners could use online feedback from EMG garments to monitor whether their running intensity is near V T2. © 2012 Institute of Physics and Engineering in Medicine.

Hu M.,Guangzhou Institute of Physical Education | Sheng J.,Guangzhou Institute of Physical Education | Kang Z.,Guangzhou University | Zou L.,Guangzhou Institute of Physical Education | And 2 more authors.
Journal of Sports Medicine and Physical Fitness | Year: 2014

The aim of this study was to examine the relation between bone marrow adipose tissue (BMAT) and bone mineral density (BMD) of lumbar spine in male professional wrestlers and healthy untrained men. A total of 14 wrestlers (22.9±3.4 years) and 11 controls (24.4±1.6 years) were studied cross-sectionally. Body composition and BMD were measured by dual-energy X-ray absorptiometry. Magnetic resonance imaging of the lumbar spine was examined in a sagittal T1-weighted (T1-w) spin-echo (SE) sequence. The averaged bone marrow signal intensity (SI) of L2-L4 was related to the signal of an adjacent nondegenerative disk. Mean SI of T1-w SE in wrestlers was lower than controls (P=0.001), indicating L2-L4 BMAT in wrestlers was lower compared to controls. L2-L4 BMD in wrestlers was higher than controls (P<0.001). In the total subject population, L2-L4 BMD was inversely correlated with mean SI of T1-w SE (r=-0.62, P=0.001). This association remained strong after adjusting for body mass and whole lean mass, but became weaker after adjusting for whole body or trunk fat percentage. The inverse relationship between BMAT and BMD was confirmed in this relatively small subject sample with narrow age range, which implies that exercise training is an important determinant of this association.

Fan Y.,Fujian Normal University | Li Z.,Jinan University | Han S.,Fujian Normal University | Lv C.,Guangzhou Institute of Physical Education | Zhang B.,Guangzhou Institute of Physical Education
Gait and Posture | Year: 2016

Walking speed is a basic factor to consider when walking exercises are prescribed as part of a training programme. Although associations between walking speed, step length and falling risk have been identified, the relationship between spontaneous walking pattern and falling risk remains unclear. The present study, therefore, examined the stability of spontaneous walking at normal, fast and slow speed among elderly (67.5 ± 3.23) and young (21.4 ± 1.31) individuals. In all, 55 participants undertook a test that involved walking on a plantar pressure platform. Foot-ground contact data were used to calculate walking speed, step length, pressure impulse along the plantar-impulse principal axis and pressure record of time series along the plantar-impulse principal axis. A forward dynamics method was used to calculate acceleration, velocity and displacement of the centre of mass in the vertical direction. The results showed that when the elderly walked at different speeds, their average step length was smaller than that observed among the young (p = 0.000), whereas their anterior/posterior variability and lateral variability had no significant difference. When walking was performed at normal or slow speed, no significant between-group difference in cadence was found. When walking at a fast speed, the elderly increased their stride length moderately and their cadence greatly (p = 0.012). In summary, the present study found no correlation between fast walking speed and instability among the elderly, which indicates that healthy elderly individuals might safely perform fast-speed walking exercises. © 2016 Elsevier B.V.

Hou Y.-L.,Guangzhou Institute of Physical Education | Peng H.,Guangzhou Institute of Physical Education
Journal of Clinical Rehabilitative Tissue Engineering Research | Year: 2010

BACKGROUND: Body composition of certain excellent athletes has been reported, however, few studies concerning the body composition of excellent long jumpers in China. OBJECTIVE: To explore the body composition and distribution of excellent long jumpers in China through determining body composition using biological resistance method. METHODS: A total of 67 long jumpers who participated in the 2005 National Athletics Championships and 2004 National University Athletics Meeting were included, 60 track-and-field specialized students and 30 university students were selected as controls. The body composition, including body fat rate, lean body mass, basal metabolic rate (BMR) and total water content were measured using "Bios pace" component analyzer with eight electrodes method. The age, gender, morphological index, and body composition were compared between the two groups. RESULTS AND CONCLUSION: The distribution features of excellent long jumpers in China were as follows: low body fat rates, body weight, and free fat body weight. The body fat rates were gradually decreased and lean body mass increased with increasing athletic levels. There were significant differences between the male and female long jumpers (P < 0.01). The lean body mass, lean body mass/height and vital capacity had positive correlation with standing long jump, standing triple jump, deep squat and special achievement, but were negatively related to 30-m running. Compared with female, the correlation coefficient of the male with lean weight was greater in male. The results are corresponding to special achievement, thus, it can provide basis for selecting and training of athletes.

Hu M.,Guangzhou Institute of Physical Education | Lin W.,Guangzhou Institute of Physical Education
Acta Haematologica | Year: 2012

Exercise training can increase total Hb and red cell mass, which enhances oxygen-carrying capacity. The possible underlying mechanisms are proposed to come mainly from bone marrow, including stimulated erythropoiesis with hyperplasia of the hematopoietic bone marrow, improvement of the hematopoietic microenvironment induced by exercise training, and hormone- and cytokine-accelerated erythropoiesis. Anemia is one of the most common medical conditions in chronic disease. The effects of exercise training on counteracting anemia have been explored and evaluated. The results of the research available to date are controversial, and it seems that significant methodological limitations exist. However, exercise training might be a promising, additional, safe and economical method to help improve anemia. There is a need for further investigation into the effects of and guidelines for exercise interventions (especially strength training) in this population of patients, particularly among cancer patients who are undergoing or have undergone chemotherapy or radiation treatments. As the available data are limited, additional research to uncover the underlying mechanisms associated with the effects of exercise training on anemia is clearly warranted. Copyright © 2012 S. Karger AG.

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