Kazuo Funato

Physiological responses to interval training sessions at velocities associated with VO2max.

Previous research has indicated that short-duration, high-intensity work intervals performed at velocities associated with maximal oxygen uptake (vVO2max) combined with active recovery intervals may be effective in eliciting improvements in endurance performance. This study was designed to characterize selected physiological responses to short-duration (< or = 60 seconds) interval work performed at velocities corresponding to 100% of vVO2max. Twelve men participated in 3 randomized trials consisting of treadmill running using work (W)/recovery (R) intervals of 15 seconds W/15 seconds R (15/15); 30 seconds W/15 seconds R (30/15); and 60 seconds W/15 seconds R (60/15). Work intervals were performed at 100% of vVO2max, whereas R intervals were performed at 50% of vVO2max. A fourth trial consisting of continuous work (C) at 100% of vVO2max was also performed. All subjects completed the 15/15 and 30/15 trials; however, only 5 of the 12 completed the 60/15 trial. The percentage of VO2max (mean +/- SD) during 15/15 (71.6 +/- 4.2%) was significantly lower (p < or = 0.05) than the percentages during 30/15 (84.6 +/- 4.0%), 60/15 (89.2 +/- 4.2%), or C (87.9 +/- 5.0%). Similar results were found for heart rate and perceived exertion. Blood lactate concentrations following exercise were significantly lower (p < or = 0.05) in 15/15 (7.3 +/- 2.4 mmol x L(-1)) than in the other trials. No significant differences (p > 0.05) existed among 30/15 (11.5 +/- 1.8 mmol x L(-1)), 60/15 (12.5 +/- 1.8 mmol x L(-1)) or C (12.1 +/- 1.8 mmol x L(-1)). High intensity, short-duration 2:1 W/R intervals appear to produce responses that may benefit both aerobic and anaerobic energy system development. A 4:1 W/R ratio may be an upper limit for individuals in the initial phases of interval training.

Muscle force per cross-sectional area is inversely related with pennation angle in strength trained athletes

The present study aimed to examine the effect of pennation angle on the force per cross-sectional area for elbow extensor muscles in strength-trained athletes. A total of 52 male bodybuilders (n = 32) and Olympic weightlifters (n = 20) did maximal isometric elbow extension on an isokinetic dynamometer. Muscle cross-sectional area (CSA) and muscle-fiber pennation angle (PA) of the triceps brachii muscles were measured by ultrasonography. Bodybuilders had significantly greater isometric elbow extension force (F), CSA and PA than weightlifters. The ratio of force to CSA (F/CSA) of bodybuilders was significantly lower than that of weightlifters. A significant positive correlation was observed between CSA and PA in both groups (r = 0.832, P < 0.001, and r = 0.682, P < 0.001, for bodybuilders and weightlifters, respectively). The F/CSA was negatively correlated to PA both for bodybuilders (r = -0.408, P < 0.05) and weightlifters (r = -0.465, P < 0.05). Thus present study indicates that the larger pennation angle is associated with the lower force relative to muscle CSA in strength-trained athletes.

Ergometry for estimation of mechanical power output in sprinting in humans using a newly developed self-driven treadmill.

Abstract An evaluation of mechanical power during walking and running in humans was undertaken after developing a specially designed running ergometer (RE) in which the subjects gripped the handlebar in front of them keeping both arms straight and in a horizontal position. Ten subjects participated in comparisons of the mean horizontal pushing force (MFam) on the handlebar with the mean horizontal ground reaction force (MFfp) recorded by force platform under the RE during five different constant speeds of walking or running and sprint running with maximal effort. Mechanical power developed during sprint running on the RE was compared with a 50 m sprint. Mean linear velocity (Mv) of the RE belt was recorded by the rotary encoder attached to the axis of the belt. Mean mechanical power calculated from the handlebar setting (MPam=MFam × Mv) was compared to that calculated from force platform recordings (MPfp=MFfp × Mv). A high test-retest reproducibility was observed for both MFfp (r=0.889) and MFam (r=0.783). Larger values for the coefficient of variation for MFam (11.3%–15.8%) were observed than for MFfp (3.3%–8.2%). The MPam, which were obtained from five different constant speeds of walking, running and sprint running were closely correlated to those of MPfp (y=0.98x − 19.10,r=0.982, P < 0.001). In sprint running, MPam was 521.7 W (7.67 W · kg−1) and was correlated to the 50 m sprint time (r=−0.683, P < 0.01). It is concluded that the newly developed RE was useful in the estimation of mechanical power output during human locomotion such as when walking, jogging and sprinting.

The development of trunk muscles in male wrestlers assessed by magnetic resonance imaging.

The purpose of this study was to compare the development of trunk musculature among Elite, Sub- elite, and Elite junior wrestlers. The performance level of these groups, ordered highest to lowest, is as follows: Elite (n = 20), Sub-elite (n = 25), and Elite junior (n = 39). A magnetic resonance imaging device was used to measure the cross-sectional area (CSA) of the trunk muscles. The whole trunk muscle cross- sectional area (t-MCSA) of the Elite group was significantly larger than that of the Elite junior group (p < 0.05). The rectus abdominis muscle CSA of the Elite group was significantly larger than that of the Elite junior group (p < 0.01). The psoas major muscle CSA of the Elite group was significantly larger than that of the Elite junior group (p < 0.05). There were no significant differences in the CSA of any of the trunk muscles between the Elite and Sub-elite groups. In conclusion, compared with Elite junior wrestlers, it is conceivable that a greater CSA of trunk flexors of Elite wrestlers is one factor which supports increased performance.

Physiological and Physical Characteristics of Elite Dragon Boat Paddlers

Abstract Ho, SR, Smith, RM, Chapman, PG, Sinclair, PJ, and Funato, K. Physiological and physical characteristics of elite dragon boat paddlers. J Strength Cond Res 27(1): 137–145, 2013—The objectives of this study were to profile the physiological and physical characteristics of elite dragon boat paddlers, to identify characteristics that predict race performance and to quantify the metabolic energy contributions to simulated 200-m and 500-m dragon boat racing. Eleven, national level, male, Japanese dragon boat paddlers completed a battery of tests on a paddling ergometer including an incremental maximal aerobic capacity test, a 2-minute maximal accumulated oxygen deficit (MAOD) test, and simulated 200-m and 500-m races. A physiological and physical profile of subjects was compiled. Results showed that 200-m race performance correlated with flexed arm girth and excess postexercise oxygen consumption (EPOC) measured in the 30 minutes after the MAOD test, whereas 500-m race performance correlated with body fat percentage, relaxed and flexed arm girth, MAOD, EPOC, and peak power during the MAOD test. Stepwise multiple regression revealed that flexed arm girth was the most powerful predictor of 200-m and 500-m race performance, followed by EPOC with the combination of these 2 factors able to explain 74% and 68% of the variance in 200-m and 500-m race performance, respectively. Aerobic energy contributions for 200-m (50 seconds) and 500-m (1 minute 50 seconds) races were (mean (95% confidence intervals)) 52.1% (range, 47.4–56.8%) and 67.5% (range, 60.1–77.8%), respectively. In conclusion, coaches should develop training programs targeted at developing upper-body musculature and increasing anaerobic capacity because these factors are the strongest predictors of 200-m and 500-m race performance. Given the substantial aerobic energy contributions even for a 200-m race event, coaches should aim to increase the maximal aerobic capacity of the paddler in preparation for both 200-m and 500-m events.

Masseter Muscle Activity in Track and Field Athletes: A Pilot Study

Teeth clenching has been shown to improve remote muscle activity (by augmentation of the Hoffmann reflex), and joint fixation (by decreased reciprocal inhibition) in the entire body. Clenching could help maintain balance, improve systemic function, and enhance safety. Teeth clenching from a sports dentistry viewpoint was thought to be important and challenging. Therefore, it is quite important to investigate mastication muscles’ activity and function during sports events for clarifying a physiological role of the mastication muscle itself and involvement of mastication muscle function in whole body movement. Running is a basic motion of a lot of sports; however, a mastication muscles activity during this motion was not clarified. Throwing and jumping operation were in a same situation. The purpose of this study was to investigate the presence or absence of masseter muscle activity during track and field events. In total, 28 track and field athletes took part in the study. The Multichannel Telemetry system was used to monitor muscle activity, and the electromyograms obtained were synchronized with digital video imaging. The masseter muscle activity threshold was set 15% of maximum voluntary clenching. As results, with few exceptions, masseter muscle activity were observed during all analyzed phases of the 5 activities, and that phases in which most participants showed masseter muscle activity were characterized by initial acceleration, such as in the short sprint, from the commencement of throwing to release in both the javelin throw and shot put, and at the take-off and landing phases in both jumps.

Estimation of Center of Gravity Obtained from 3D Whole Body Scanning Anthropometry Method

Introduction: In the past, body segmental volume was measured from various methods as immersion method, mathematical model, photogrammetric, have been used for various research in biomechanics. As for the three dimensional anthropometry how there are a whole body volume and each segment volumes, possibility of estimation of various body segment parameter will be shown. Purpose of this study was estimated center of mass using three dimensional anthropometry. Methods: The subjects were 6 males (Age:22.3±1.1 years, body height: 172.5±5.9cm, body mass: 67.2±2.5kg) participated in this study. We used Body line scanner ( BLS: Hamamatsu Photonics KK) for 3D Whole body anthropometry. Subjects were measured a whole body volume using BLS. Scanning data obtained from BLS was distributed 14 parts of each segmental volumes using anatomical randmarkpoint, be calculated each segmental volumes. For the definition of each segment were used from C.E.Clauser,1969. Center of each segmental mass (SCOM) was calculated from each segmental volume. Segment mass (SM) was calculated using each segment density which from preceding study. Center of gravity (COGABS) and COGREL (center of gravity expressed as a percentage of the body height) was calculated from SCOM and SM of each segment. For the measurement of the COGABS and COGREL, the reaction board method was employed. The reaction board consisted of a rigid board (180×91.5×2.5cm) mounted on a scale. COGABS and COGREL were compared from each method that calculated from reaction board , BLS and predicted value from C.E.Clauser,1969 , and calculated %Difference. Results and Discussion: The whole body mass that we estimated using BLS compared with body weight, the difference was under 1.5%. %difference of COGABS and COGREL (BLS and a measurement) were 2.9±0.9%, and the BLS showed lower than measurement (measured:COGABS =97.2±3.6cm,COGREL=56.6±0.5%,BLS:COGABS=94.4±3.0cm,COGREL=54.9±0.5%). In addition, the predicted value showed higher than a measurement (predicted value:COGABS=100.1± 3.5cm,COGREL=58.3±0.6%). Conclusion: It was suggested that We can estimate COG which we estimated from segment mass and center of volume with an measured and a difference of 2.9% .

Applications of 3D Body Scanning Technology to Human Anthropometry: Body Surface Area and Body Volume Measurements in the Fields of Health and Sports Sciences

In the fields of sports and health sciences, changes in body shape are one of the most important parameters in order to evaluate the effects of physical training and /or routine workout performed. Until now, these parameters were typically measured under manually skilled techniques in anthropometry. In recent years, Whole body measurement system for humans (that is called “Bodyline Scanner”, Hamamatsu Photonics K.K., Japan) which has functions such as a high speed measurement and high resolutions are required by many industrial and academic areas such as apparel and digital technology. The purposes of present study were to develop 3D anthropometry by optical triangle method using laser beam system and to determine feasibility of the measurements such as lengths, circumferences, body surface area (BSA) and body/segment volumes with comparing to other conventional methods. Newly developed Bodyline scanner (BLS) as shown in Fig.1 was capable of digitizing whole body shape as three dimensional coordinates in the order of 2.5mm intervals in space (normal adult body shape put in ~500,000 points). The principle of the measuring method was optical triangle measurement, in which light source was using a laser diode. The color information was used to detect the position of land mark seals which was pasted on the skin according to the anatomical basis in human anthropometry. Six moving scanner heads and intelligent vision camera systems were enable to reduce the area which can not measure those positions such armpit and crotch, and to reduce whole body scanning time up to ten seconds. Measuring height was as much as 2300 mm which enable to scan whole body from children to such one as Olympic basketball athletes. 3D polygon data reconstructed after digitizing each point was used for the measurement of anthropometry such as lengths and circumferences of each limb or trunk, body surface area (BSA) and each segment volumes or whole body volume. Sixty seven males and females aged from 9 to 21yrs were tested in both BLS and manually conventional tape measure methods (TAPE). Differences of lengths and circumferences of the limbs between BLS and TAPE were within 4%. BSA data was almost identical to those estimated from the equation based on body height and weight ( Du Bois, 1916). Whole body volume data obtained from BLS were precisely consistent with those obtained from air displacement methods. Anthropometric data as well as body surface area and body volume measured by using 3D body scanning technologies might be widely prospective for evaluating the differences or changes in body shape in such fields as health and sports sciences.

Measurement of specific movement power for estimation of athletic performance

In the final of the long jump at the third World Championships in 1991, a new world record, 8. 95m, was set by Mike Powell. Carl Lewis also exceeded the previous world record with a leap of 8.91m. The jumps of finalists were filmed by three high-speed cameras (100-200 f/s). The films were analyzed by using the DLT method. The purpose of this study was to ccmpare the kinematical characteristics of take-off motion of Powell and Lewis. Although the run-up velocity (l l.OOm/s) of Powell was same as that (ll.O6m/s) of Lewis, the projectron angles were different. The jumps of Powell (23.2deg) and Lewis (18.3deg) may be described as ‘high’ and ‘low’ jumps respectively in elite male long jumpers . The projection angle could depend upon the following take-off motions: (1)Powell’s the center of gravity in the vertical position was lower than that of Lewis at touch-down: (2)Powell leant further backwards than Lewis at touch-down; (3)Powell’s knee extension of the supporting leg during take-off was greater than Lewis’s: (4)Although the rotations of the trunk during take-off were almost the same, Powell’s trunk rotation was mainly supported by hip rotation, while in Lewis’s case it was mainly supported by shoulder rotation. It could be inferred that Powell achieves a greater vertical velocity and higher angle of take-off by using the trunk inclination, the extended supporting leg and the hip rotation: Lewis on the other hand relies on the flexed supporting leg, the shoulder rotation and the lower angle of take-off, whrch facilitates a relatively high horizontal velocity. ACKNOWLEDGMENT: This study was supported by the JMFIIAAF Biomechanlcs Research Project Team.