Michiya Tanimoto

Effects of whole-body low-intensity resistance training with slow movement and tonic force generation on muscular size and strength in young men.

Tanimoto, M, Sanada, K, Yamamoto, K, Kawano, H, Gando, Y, Tabata, I, Ishii, N, and Miyachi, M. Effects of whole-body low-intensity resistance training with slow movement and tonic force generation on muscular size and strength in young men. J Strength Cond Res 22(6): 1926-1938, 2008-Our previous study showed that relatively low-intensity (~50% one-repetition maximum [1RM]) resistance training (knee extension) with slow movement and tonic force generation (LST) caused as significant an increase in muscular size and strength as high-intensity (~80% 1RM) resistance training with normal speed (HN). However, that study examined only local effects of one type of exercise (knee extension) on knee extensor muscles. The present study was performed to examine whether a whole-body LST resistance training regimen is as effective on muscular hypertrophy and strength gain as HN resistance training. Thirty-six healthy young men without experience of regular resistance training were assigned into three groups (each n = 12) and performed whole-body resistance training regimens comprising five types of exercise (vertical squat, chest press, latissimus dorsi pull-down, abdominal bend, and back extension: three sets each) with LST (~55-60% 1RM, 3 seconds for eccentric and concentric actions, and no relaxing phase); HN (~80-90% 1RM, 1 second for concentric and eccentric actions, 1 second for relaxing); and a sedentary control group (CON). The mean repetition maximum was eight-repetition maximum in LST and HN. The training session was performed twice a week for 13 weeks. The LST training caused significant (p < 0.05) increases in whole-body muscle thickness (6.8 ± 3.4% in a sum of six sites) and 1RM strength (33.0 ± 8.8% in a sum of five exercises) comparable with those induced by HN training (9.1 ± 4.2%, 41.2 ± 7.6% in each measurement item). There were no such changes in the CON group. The results suggest that a whole-body LST resistance training regimen is as effective for muscular hypertrophy and strength gain as HN resistance training.

Poor trunk flexibility is associated with arterial stiffening

Flexibility is one of the components of physical fitness as well as cardiorespiratory fitness and muscular strength and endurance. Flexibility has long been considered a major component in the preventive treatment of musculotendinous strains. The present study investigated a new aspect of flexibility. Using a cross-sectional study design, we tested the hypothesis that a less flexible body would have arterial stiffening. A total of 526 adults, 20 to 39 yr of age (young), 40 to 59 yr of age (middle-aged), and 60 to 83 yr of age (older), participated in this study. Subjects in each age category were divided into either poor- or high-flexibility groups on the basis of a sit-and-reach test. Arterial stiffness was assessed by brachial-ankle pulse wave velocity (baPWV). Two-way ANOVA indicated a significant interaction between age and flexibility in determining baPWV (P < 0.01). In middle-aged and older subjects, baPWV was higher in poor-flexibility than in high-flexibility groups (middle-aged, 1,260 +/- 141 vs. 1,200 +/- 124 cm/s, P < 0.01; and older, 1,485 +/- 224 vs. 1,384 +/- 199 cm/s, P < 0.01). In young subjects, there was no significant difference between the two flexibility groups. A stepwise multiple-regression analysis (n = 316) revealed that among the components of fitness (cardiorespiratory fitness, muscular strength, and flexibility) and age, all components and age were independent correlates of baPWV. These findings suggest that flexibility may be a predictor of arterial stiffening, independent of other components of fitness.

Resistance training in men is associated with increased arterial stiffness and blood pressure but does not adversely affect endothelial function as measured by arterial reactivity to the cold pressor test

Resistance training is a popular mode of exercise, but may result in stiffening of the central arteries. Changes in carotid artery diameter were determined using the cold pressor test (CPT), which results in production of nitric oxide via sympathetic activation and is one of the novel methods available for assessing endothelial function in the carotid artery. To investigate the effect of resistance training on endothelial function, we designed a cross‐sectional study of carotid arterial vasoreactivity to CPT in men participating in regular resistance training with increased carotid arterial stiffness compared with age‐matched control subjects. Twelve resistance‐trained middle‐aged men (age 38.7 ± 1.7 years) and 17 age‐matched control subjects (age 36.8 ± 1.2 years) were studied. The direction and magnitude of changes in carotid artery diameter were measured by B‐mode ultrasonography during sympathetic stress induced by submersion of the foot in ice slush for 90 s. Carotid arterial β‐stiffness index, and systolic and mean arterial blood pressure were higher (7.7 ± 0.7 versus 6.0 ± 0.4 arbitrary units, 116 ± 2 versus 131 ± 4 mmHg and 86 ± 2 versus 95 ± 2 mmHg, respectively, all P < 0.05) in the resistance training group compared with control subjects. There were, however, no significant differences in the amount or percentage change in carotid artery diameter in CPT between the two groups (resistance training group, 0.33 ± 0.07 mm and 5.2 ± 1.1%; control group, 0.37 ± 0.06 mm and 5.8 ± 0.9%, respectively). These findings suggest that while carotid arterial stiffening and higher blood pressure are observed in regular resistance‐trained men, these are not associated with abnormalities in carotid arterial vasoreactivity to sympathetic stimulus, which implies intact endothelial function.

Age and cardiorespiratory fitness are associated with arterial stiffening and left ventricular remodelling

Arterial stiffening, hypertension and left ventricular (LV) remodelling are associated with increased risk of cardiovascular disease. Cardiorespiratory fitness is associated with cardiovascular function and reduced risk of cardiovascular disease. This cross-sectional study was carried out to determine the relationships between cardiorespiratory fitness, arterial stiffness, blood pressure (BP) and LV remodelling in women. On the basis of peak oxygen uptake, a total of 159 premenopausal (young) and postmenopausal (older) women were categorized into either low (unfit) or high (fit) cardiorespiratory fitness groups. The arterial stiffness and LV remodelling were measured by brachial-ankle pulse wave velocity (baPWV) and carotid augmentation index (AI) and LV relative wall thickness (RWT). Two-way analysis of variance indicated a significant interaction between age and cardiorespiratory fitness in baPWV, carotid AI, BP and RWT. In the older group, arterial stiffness (baPWV; 1401±231 vs 1250±125 cm s–1, P<0.01, AI; 32.9±9.9 vs 24.8±10.1%, P<0.01), systolic blood pressure (SBP) (130±22 vs 117±15 mm Hg, P<0.01) and RWT (0.47±0.08 vs 0.42±0.04, P<0.05) in fit women were lower than in unfit women. In older women, RWT was significantly related to baPWV (r=0.46, P<0.01), carotid AI (r=0.29, P<0.05), SBP (r=0.57, P<0.01) [Vdot ]2peak (r=−0.32, P<0.05). In young women, they were not significant correlations, except for a weak correlation between RWT and SBP (r=0.21, P<0.05). These results suggest that higher cardiorespiratory fitness is associated with lower arterial stiffness, BP and RWT in older women.

Effects of training volume on strength and hypertrophy in young men.

Abstract Sooneste, H, Tanimoto, M, Kakigi, R, Saga, N, and Katamoto, S. Effects of training volume on strength and hypertrophy in young men. J Strength Cond Res 27(1): 8–13, 2013—Knowledge of the effects of training volume on upper limb muscular strength and hypertrophy is rather limited. In this study, both arms of the same subject were trained in a crossover-like design with different training volumes (1 or 3 sets) to eliminate the effects of genetic variation and other individual differences. The purpose of this study was to investigate the effects of training volume on muscular strength and hypertrophy in sedentary, untrained young Japanese men. Eight subjects (age, 25.0 ± 2.1 years; body mass, 64.2 ± 7.9 kg; height, 171.7 ± 5.1 cm) were recruited. The subjects trained their elbow flexor muscles twice per week for 12 consecutive weeks using a seated dumbbell preacher curl. The arms were randomly assigned to training with 1 or 3 sets. The training weight was set at 80% of 1 repetition maximum for all sets. The 3-set protocol increased cross-sectional area significantly more than did 1 set (1 set, 8.0 ± 3.7%; 3 sets, 13.3 ± 3.6%, p < 0.05). Furthermore, gains in strength with the 3-set protocol tended to be greater than those with 1 set (1 set, 20.4 ± 21.6%; 3 sets, 31.7 ± 22.0%, p = 0.076). Based on the results, the authors recommend 3 sets for sedentary untrained individuals. However, this population should incorporate light training days of 1 set into their training program to prevent overtraining and ensure adherence. The findings are relevant for the sedentary, untrained young male population and must be interpreted within the context of this study.

Low-intensity resistance training with slow movement and tonic force generation increases basal limb blood flow.

Metabolic syndrome is associated with reductions in basal limb blood flow. Resistance training increasing muscle mass and strength increases basal limb blood flow. Low‐intensity resistance exercise with slow movement and tonic force generation (LST) has been proposed as one of the effective methods of resistance training increasing muscle mass and strength. The hypothesis that LST training increases basal femoral blood flow as well as traditional high‐intensity resistance training at normal speed (HN) was examined. Thirty‐six healthy young men without a history of regular resistance training were randomly assigned to the LST [∼55–60% one repetition maximum (1RM) load, 3 s lifting and 3 s lowering with no relaxation phase, n = 12], HN (∼85–90% 1RM, 1 s lifting and 1 s lowering with 1 s relaxation, n = 12) or sedentary control (CON, n = 12) groups. Participants in the training groups underwent two whole‐body training sessions per week for 13 weeks. Basal femoral blood flow increased significantly by +18% in LST and +35% in HN (both P<0·05), while there was no such change in CON. There were no significant differences between these increases induced by LST and HN, although the increase in LST corresponded to about half that in HN. In conclusion, not only resistance training in HN but in LST as well, were effective for increasing basal limb blood flow, and that this effect was evident even in healthy young men.

Muscle mass and bone mineral indices: does the normalized bone mineral content differ with age?

Objective:To investigate the relationships between regional skeletal muscle mass (SM mass) and bone mineral indices and to examine whether bone mineral content (BMC) normalized to SM mass shows a similar decrease with age in young through old age.Subjects/Methods:One hundred and thirty-eight young and postmenopausal women aged 20–76 years participated in this study and were divided into three groups: 61 young women, 49 middle-aged postmenopausal women and 28 older postmenopausal women. Muscle thickness (MTH) was determined by ultrasound, and regional SM mass (arm, trunk and leg) was estimated based on nine sites of MTH. Whole-body and regional lean soft tissue mass (LSTM), bone mineral density (BMD) and BMC (whole body, arms, legs and lumbar spine) were measured using dual-energy X-ray absorptiometry.Results:Ultrasound spectroscopy indicated that SM mass is significantly correlated with site-matched regional bone mineral indices and these relationships correspond to LSTM. The BMC and BMD in older women were significantly lower than those in middle-aged women. When BMC was normalized to site-matched regional SM mass, BMC normalized to SM mass in arm and trunk region were significantly different with age; however, whole-body and leg BMC normalized to SM mass showed no significant difference between middle-aged and older postmenopausal women.Conclusions:The age-related differences in BMC were found to be independent of the ageing of SM mass in the arm and trunk region. However, differences in BMC measures of the leg and whole body were found to correspond to age-related decline of SM mass in postmenopausal women.

Effect of resistance training using bodyweight in the elderly: Comparison of resistance exercise movement between slow and normal speed movement

The present study investigated whether a slow movement protocol can be applied to resistance training using bodyweight. In addition, the intervention program combined plyometric exercise with resistance exercise to improve physical function overall.

Required muscle mass for preventing lifestyle-related diseases in Japanese women.

BackgroundSince it is essential to maintain a high level of cardiorespiratory fitness to prevent life-style related disease, the Ministry of Health, Labour and Welfare of Japan in 2006 proposed to determine the maximal oxygen uptake (Vo2max: mL·kg-1·min-1) reference values to prevent life-style related diseases (LSRD). Since muscle mass is one of the determinant factors of Vo2max, it could be used as the reference parameter for preventing LSRD. The aim of this study was to determine and quantify the muscle mass required to maintain the Vo2max reference values in Japanese women.MethodsA total of 403 Japanese women aged 20–69 years were randomly allocated to either a validation or a cross-validation group. In the validation group, a multiple regression equation, which used a set of age and the percentage of muscle mass (%MM, percentage of appendicular lean soft tissue mass to body weight), as independent variables, was derived to estimate the Vo2max. After the equation was cross-validated, data from the two groups were pooled together to establish the final equation. The required %MM for each subject was recalculated by substituting the Vo2max reference values and her age in the final equation.ResultsThe mean value of required %MM was identified as (28.5 ± 0.35%). Thus, the present study proposed the required muscle mass (28.5% per body weight) in Japanese women to maintain the Vo2max reference values determined by the Japanese Ministry of Health Labour and Welfare.ConclusionThe estimated required %MM (28.5% per body weight) can be used as one of the reference parameters of fitness level in Japanese women.

Changes in Muscle Activation and Force Generation Patterns During Cycling Movements Because of Low-Intensity Squat Training With Slow Movement and Tonic Force Generation

Tanimoto M, Arakawa H, Sanada K, Miyachi M, and Ishii N. Changes in muscle activation and force generation patterns during cycling movements because of low-intensity squat training with slow movement and tonic force generation. J Strength Cond Res 23(8): 2367-2376, 2009-Our previous studies showed that relatively low-load (∼50-60% 1 repetition maximum [1RM]) resistance training with slow movement and tonic force generation (LST) significantly increased muscle size and strength. However, LST is a very specific movement that differs from natural movements associated with sport activities and activities of daily life, and therefore, it might have some unfavorable effects on dynamic sport movement. We investigated the effects of LST on muscle activity and force generation patterns during cycling movement as a representative dynamic sports movement. Twenty-four healthy young men who were not in the habit of bicycle riding and did not have a history of regular resistance training were randomly assigned to the LST (∼60% 1RM load, 3-second lifting, and 3-second lowering movement without a relaxing phase: n = 8), a high-intensity exercise at normal speed (HM) group (85% 1RM load, 1-second lifting, 1-second lowering, and 1-second relaxed movement: n = 8), or sedentary control (CON, n = 8) group. Subjects in the training groups performed vertical squats by the assigned method. Exercise sessions consisted of 3 sets and were performed twice a week for 13 weeks. Pre- and posttraining muscle activation and force generation patterns during the cycling movements were evaluated by the coefficient of variation (CV) of the rectified electromyographic (EMG) wave from the vastus lateralis and CV of pedaling force. Both the CV of the rectified EMG and of pedaling force decreased significantly in the LST group (−21 and −18%, p < 0.05, respectively), whereas there were no significant changes in either the HN or the CON group. This decrease in CV in the LST group could mean that muscle activity and force generation during cycling movement have become more tonic. This result following LST may have an unfavorable effect on cycling movement and other dynamic sports movements.