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Madoka Ogawa, Naotoshi Mitsukawa, Michael G. Bemben and Takashi Abe

Context:

Previous studies investigated the relationship between ultrasound-derived anatomical muscle thickness (MTH) and individual muscle cross-sectional area (CSA) and muscle volume in several limb and trunk muscles; however, the adductor muscle that contributes to hip adduction and pelvic stabilization, as well as balance ability, has not been studied.

Objective:

To examine the relationship between MTH of the lower, middle, and upper thigh measured by B-mode ultrasound and the muscle CSA and volume of adductor muscle obtained by magnetic resonance imaging (MRI) to confirm the possibility of predicting adductor muscle CSA/volume using ultrasound-derived MTH.

Setting:

University research laboratory.

Subjects:

10 men and 10 women (20–41 y old) volunteered to participate in this study.

Main Outcome Measures:

A series of continuous muscle CSAs along the thigh were measured by MRI scans (1.5-T scanner, GE Signa). In each slice, the anatomical CSA of the adductors was analyzed, and the muscle volume was calculated by multiplying muscle CSA by slice thickness. Thigh MTH was measured by B-mode ultrasound (Aloka SSD-500) at 5 sites (anterior 30%, 50%, and 70% and posterior 50% and 70% of thigh length).

Results:

A strong correlation was observed between anterior 30% MTH and 30% adductor CSA in men (r = .845, P < .002) and women (r = .952, P < .001) and in both groups combined (r = .922, P < .001). Anterior 30% MTH was also strongly correlated to adductor muscle volume when combined with thigh length (n = 20, r = .949, P < .001). However, there were moderate or nonsignificant correlations between anterior and posterior 50% and 70% MTH and adductor muscle CSA/volume.

Conclusions:

The results suggest that MTH in the upper portion of anterior thigh best reflects adductor muscle CSA or muscle volume, while the lower portions of the anterior and posterior sites are least likely to predict adductor muscle size.

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Takashi Abe, Jeremy P. Loenneke, Robert S. Thiebaud and Mark Loftin

Context: Studies developed the frail elderly handgrip strength (HGS) diagnostic criteria using multiple types of handgrip dynamometers. If different handgrip dynamometers report different values, then this would have the potential to misclassify people into the wrong diagnostic category. Objective: To examine the characteristics of HGS measured by 2 standard handgrip dynamometers and to investigate the influence of hand size on HGS. Setting: University research laboratory. Participants: A total of 87 young and middle-aged adults between the ages of 20 and 60 years participated in this study. Main Outcome Measures: Standard methods of HGS measurements were used for hydraulic and Smedley spring-type dynamometers, although the participants were instructed to maintain an upright standing position in both tests. Results: Test–retest reliability of hydraulic and Smedley dynamometers provided comparable results to that observed with previous studies. However, the difference in HGS between the 2 dynamometers (Hydraulic–Smedley difference) was positively associated (r = .670, P < .001) with the mean of the 2 dynamometers. The participants who had relatively low HGS (at least <35 kg) produced similar HGS values when the 2 dynamometers were compared, whereas persons who had relatively higher HGS (at least >45 kg) produced greater strength values with the hydraulic compared with the Smedley. The hand and palm lengths were weakly correlated (r = .349 and r = .358, respectively, both Ps < .001) with the difference in HGS between the 2 dynamometers. Conclusions: Test–retest reliability of hydraulic and Smedley dynamometers provides comparable results to previous studies. However, the difference in HGS between the 2 dynamometers was positively associated with the mean of the 2 dynamometers. This Hydraulic–Smedley difference would not affect persons who have relatively low HGS (at least <35 kg), while when HGS is relatively high, the comparison between dynamometers should be done with caution.

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Kosuke Kojima, Christopher L. Brammer, Tyler D. Sossong, Takashi Abe and Joel M. Stager

Purpose: The purpose of this study is to compare the efficacy of resisted sprint swim training with that of nonresisted sprint swim training on 50-m freestyle competition time (Vmax50) in age-group swimmers. Methods: Twenty-four age-group swimmers (age 10.6–14.9 y) were divided into resisted or nonresisted sprint swim training groups and completed a sprint swim training intervention 2 times per week for 10 weeks. Repeated 10-m sprints with progressively increasing resistance were used to determine measures of swim power. Skeletal muscle mass was estimated using B-mode ultrasound. Maturity status was estimated using predicted adult height (%Htadult) and maturity offset. Results: A 2-way repeated-measures analysis of variance revealed no group × time interaction for measured variables. Vmax50 was correlated with skeletal muscle mass and swim power variables, but no significant relationship was found between relative changes in these variables. Estimated maturity status (%Htadult) appeared to be associated with initial measures of swim power and performance variables. Conclusions: Ten weeks of resisted sprint swim training was not any more effective than nonresisted sprint swim training at improving sprint swim performance in age-group swimmers.

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Robert S. Thiebaud, Takashi Abe, Jeremy P. Loenneke, Tyler Garcia, Yohan Shirazi and Ross McArthur

Context: Blood flow restriction (BFR) increases muscle size and strength when combined with low loads, but various methods are used to produce this stimulus. It is unclear how using elastic knee wraps can impact acute muscular responses compared with using nylon cuffs, where the pressure can be standardized. Objective: Investigate how elastic knee wraps compare with nylon cuffs and high-load (HL)/low-load (LL) resistance exercise. Design: A randomized cross-over experimental design using 6 conditions combined with unilateral knee extension. Setting: Human Performance Laboratory. Participants: A total of 9 healthy participants (males = 7 and females = 2) and had an average age of 22 (4) years. Intervention: LL (30% of 1-repetition maximum [1-RM]), HL (70% 1-RM), BFR at 40% of arterial occlusion pressure (BFR-LOW), BFR at 80% of arterial occlusion pressure (BFR-HIGH), elastic knee wraps stretched by 2 in (PRACTICAL-LOW), and elastic knee wraps stretched to a new length equivalent to 85% of thigh circumference (PRACTICAL-HIGH). BFR and practical conditions used 30% 1-RM. Main Outcome Measures: Muscle thickness, maximum voluntary isometric contraction, and electromyography amplitude. Bayesian statistics evaluated differences in changes between conditions using the Bayes factor (BF10), and median and 95% credible intervals were reported from the posterior distribution. Results: Total repetitions completed were greater for BFR-LOW versus PRACTICAL-HIGH (BF10 = 3.2, 48.6 vs 44 repetitions) and greater for PRACTICAL-LOW versus BFR-HIGH (BF10 = 717, 51.8 vs 36.3 repetitions). Greater decreases in changes in maximum voluntary isometric contraction were found in PRACTICAL-HIGH versus HL (BF10 = 1035, ∼103 N) and LL (BF10 = 45, ∼66 N). No differences in changes in muscle thickness were found between LL versus PRACTICAL-LOW/PRACTICAL-HIGH conditions (BF10 = 0.32). Greater changes in electromyography amplitude were also found for BFR-LOW versus PRACTICAL-HIGH condition (BF10 = 6.13, ∼12%), but no differences were noted between the other BFR conditions. Conclusions: Overall, elastic knee wraps produce a more fatiguing stimulus than LL or HL conditions and might be used as an alternative to pneumatic cuffs that are traditionally used for BFR exercise.

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Zachary W. Bell, Scott J. Dankel, Robert W. Spitz, Raksha N. Chatakondi, Takashi Abe and Jeremy P. Loenneke

Context: The perceived tightness scale is suggested to be an effective method for setting subocclusive pressures with practical blood flow restriction. However, the reliability of this scale is unknown and is important as the reliability will ultimately dictate the usefulness of this method. Objective: To determine the reliability of the perceived tightness scale and investigate if the reliability differs by sex. Design: Within-participant, repeated-measures. Setting: University laboratory. Participants: Twenty-four participants (12 men and 12 women) were tested over 3 days. Main Outcome Measures: Arterial occlusion pressure (AOP) and the pressure at which the participants rated a 7 out of 10 on the perceived tightness scale in the upper arm and upper leg. Results: The percentage coefficient of variation for the measurement was approximately 12%, with no effect of sex in the upper (median δ [95% credible interval]: 0.016 [−0.741, 0.752]) or lower body (median δ [95% credible interval]: 0.266 [−0.396, 0.999]). This would produce an overestimation/underestimation of ∼25% from the mean perceived pressure in the upper body and ∼20% in the lower body. Participants rated pressures above their AOP for the upper body and below for the lower body. At the group level, there were differences in participants’ ratings for their relative AOP (7 out of 10) between day 1 and days 2 and 3 for the lower body, but no differences between sexes for the upper or lower body. Conclusions: The use of the perceived tightness scale does not provide reliable estimates of relative pressures over multiple visits. This method resulted in a wide range of relative AOPs within the same individual across days. This may preclude the use of this scale to set the pressure for those implementing practical blood flow restriction in the laboratory, gym, or clinic.