William F. Brechue

Water-based exercise improves health- related aspects of fitness in older women

PURPOSE The purpose of this study was to determine the physiological responses of elderly women to a well-rounded exercise program performed in water (WEX). METHODS The participants (60-75 yr of age) were randomly divided into a training (TR) group (N = 15) and a control group (N = 15). The TR group participated in a 12-wk supervised WEX program, 70 min x day(-1), 3 d x wk(-1). The WEX consisted of 20 min of warm-up and stretching exercise, 10 min of resistance exercise, 30 min of endurance-type exercise (walking and dancing), and 10 min of cool-down exercise. RESULTS The WEX led to an increase (P < 0.05) in peak VO2 (12%) and VO2 at lactate threshold (20%). Muscular strength evaluated by a hydraulic resistance machine increased significantly at resistance dial setting 8 (slow) for knee extension (8%), knee flexion (13%), chest press (7%) and pull (11%), shoulder press (4%) and pull (6%), and back extension (6%). Vertical jump (9%), side-stepping agility (22%), trunk extension (11%), and FEV1.0 (7%) also increased significantly. There was a significant decrease in skin-fold thickness (-8%), low-density lipoprotein (LDL) cholesterol (-17%), and total cholesterol (-11%). There were no significant changes in these variables in the control group. CONCLUSION These results indicate that WEX elicits significant improvements in cardiorespiratory fitness, muscular strength, body fat, and total cholesterol in older adult women. Water-based exercise appears to be a very safe and beneficial mode of exercise that can be performed as part of a well-rounded exercise program.

Fascicle length of leg muscles is greater in sprinters than distance runners.

PURPOSE The purpose of this study was to compare architectural characteristics of leg muscles of sprinters and distance runners. METHODS Skeletal muscle architectural characteristics were studied in 23 elite male 100-m sprinters (SPR, 10.0-10.9 s for 100 m), 24 elite male distance runners (DR, 13.5-14.5 min for 5000 m), and 24 untrained male controls. Fascicle pennation angle and isolated muscle thickness of the vastus lateralis and gastrocnemius medialis and lateralis muscles were measured in vivo by ultrasound, and fascicle length was estimated. RESULTS Standing height and upper and lower limb lengths were similar among the groups. Body weight was significantly greater in SPR than in either DR or controls, which were similar. Muscle thickness of the vastus lateralis and gastrocnemius medialis and lateralis muscles was significantly greater in SPR than in either DR or controls, which were similar. In all muscles, pennation angle was similar between SPR and controls, but less than DR. Fascicle length of the vastus lateralis muscle (absolute and relative to limb length) was greatest in SPR and least in DR with control values being between the athlete groups. Fascicle length of the gastrocnemius medialis muscle (absolute and relative to limb length) was greater in SPR than in either DR or controls, which were similar. Fascicle length of the gastrocnemius lateralis muscle (absolute and relative to limb length) was significantly greater in SPR than DR. Absolute fascicle length in gastrocnemius lateralis muscle was similar between DR and controls; however, relative to limb length DR was significantly less. CONCLUSION Greater fascicle length and lesser pennation angle observed in leg muscles of SPR, compared with DR, would appear to favor shortening velocity as required for greater running speed.

Effect of resistance training volume on strength and muscle thickness

The purpose of this study was to determine the effects of different volumes of high-intensity resistance training on isometric torque and muscle thickness. Training was conducted three times per week using one set (low volume, EX-1, N = 18) or three sets (high volume, EX-3, N = 20) of dynamic variable resistance exercise. Ten subjects acted as nontraining controls (CONT). Bilateral knee extension (KEXT) and flexion (KFLEX) exercise was performed to fatigue within 8-12 repetitions for 14 wk. Maximal isometric KEXT and KFLEX torque was tested at 6 degrees, 24 degrees, 42 degrees, 60 degrees, 78 degrees, 96 degrees, and 108 degrees of KFLEX using a MedX (Ocala, FL) KEXT/KFLEX ergometer. The anterior (ANT), lateral (LAT), and posterior (POST) right thigh, the medialis muscle (MED), and the lateralis muscle (LATER) were assessed for thickness by B-mode ultrasound (ULTRA). Both training groups improved torque output at most angles, but there was no difference between EX-1 and EX-3 (P > or = 0.05). ULTRA detected increases in muscle thickness for EX-1 at 60% LAT and 40% and 60% POST. EX-3 increased muscle thickness at the MED, and 40% and 60% POST. In conclusion, one set of high intensity resistance training was as effective as three sets for increasing KEXT and KFLEX isometric torque and muscle thickness in previously untrained adults.

Exercise training in the debilitated aged: Strength and functional outcomes

OBJECTIVE Resistance and endurance training result in gains in fitness in the aged. It is unclear whether the debilitated elderly can perform moderate-intensity training and whether such training results in short-term improvements in strength, endurance, and function in this population. DESIGN Randomized, controlled trial. SETTINGS AND PATIENTS Subjects were from a Veterans Affairs nursing home and rehabilitation unit and a community nursing home. They were older than 60 yrs with impairment in at least one physical activity of daily living. Seventy-eight subjects volunteered and 58 (mean age, 75 yrs; 9 women, 49 men) completed the intervention and initial posttest. Only one subject withdrew because of injury or disinterest. INTERVENTION Thrice-weekly resistance training (using an isokinetic dynamometer) and twice-weekly endurance training for 4 to 8 weeks. MAIN OUTCOMES Isometric strength in dominant arm and leg, heart rate response to timed endurance test, and activities of daily living score. RESULTS The mean change in isometric strength across the muscle movements tested was 32.8% in the training group and 10.2% in the control group (difference, 22.6%; 95% confidence interval, 6.2% to 39.0%). No change in heart rate during exercise was seen in the training group. Trained subjects tended to have a greater improvement in functional activity than control subjects, which was statistically significant (p = .04) for those subjects who at enrollment were most dysfunctional (i.e., activities of daily living score less than 13 [maximum score 26]). CONCLUSION This group of debilitated elderly patients effectively performed resistance training and increased their strength, with the most impaired gaining the most function. Few in the group could effectively perform endurance training.

Muscle activation during low-intensity muscle contractions with restricted blood flow

Abstract We examined muscle activation during low-intensity muscle contractions with a moderate restriction of blood flow and complete occlusion of blood flow. Unilateral elbow flexion muscle contractions (20% of 1-RM) were performed in Experiment 1 (30 contractions), Experiment 2 (3 sets × 10 contractions), and Experiment 3 (30 repetitive contractions followed by 3 sets × 15 contractions) with moderate restriction, complete occlusion of blood flow or unrestricted blood flow (control). Electromyography (EMG) was recorded from surface electrodes placed on the biceps brachii muscle and the integrated EMG (iEMG) and mean power frequency (MPF) obtained. During Experiments 1 and 2, muscle activation was progressively increased in complete occlusion and moderate restriction of blood flow to levels greater than in the control. The decline in maximal voluntary isometric contraction (MVC) following the bout of contractions was greater with complete occlusion (39–48%) than moderate restriction of blood flow (16–19%); control MVC did not change. In Experiment 3, changes in MVC, iEMG, and MPF were greater with moderate restriction of blood flow than in the control but comparable with complete occlusion of blood flow where less total work was performed. In conclusion, moderate restriction of blood flow results in similar neural manifestations in muscle as complete occlusion of blood flow but without the apparent contractile/metabolic impairment observed with complete occlusion. Thus, low-intensity muscle contractions, with moderate restriction of blood flow, leads to more intense activation of the muscle relative to the external load.

Gender differences in FFM accumulation and architectural characteristics of muscle

PURPOSE The purpose of this study was to gain insight into the skeletal muscle development potential in women and to evaluate the contribution of muscle pennation angle (PANG) and fascicle length to gender differences in muscle size or FFM accumulation. METHODS Skeletal muscle architectural characteristics and FFM were studied in 29 strength-trained female and 22 age- and height-matched male college athletes. Muscle thickness (MTH) was measured by B-mode ultrasound at 13 anatomical sites. Isolated MTH and PANG of the triceps long head (TL), vastus lateralis (VL), and gastrocnemius medialis (MG) muscles were measured in vivo, and fascicle length was estimated. RESULTS Six female athletes had more than 60 kg of FFM, with the largest being 82.1 kg. In general, male athletes had a significantly greater FFM and MTH at all sites except for the anterior thigh. Isolated MTH and PANG of the TL, VL, and MG were greater in males. There were no gender differences in limb length or fascicle length of the three isolated muscles. A significant correlation was observed between MTH and PANG for TL (r = 0.84) and MG (r = 0.41), but not for VL. CONCLUSIONS In contrast to previous estimates, we conclude that the theoretical upper limit of FFM accumulation and FFM-to-height ratio in women is greater than 80 kg and 0.44 kg.cm-1, respectively. Gender differences in PANG appear to be related to differences in muscle size (MTH) and do not appear to contribute independently to the gender difference in FFM.

The role of FFM accumulation and skeletal muscle architecture in powerlifting performance.

Abstract. The purpose of this study was to determine the distribution and architectural characteristics of skeletal muscle in elite powerlifters, and to investigate their relationship to fat-free mat (FFM) accumulation and powerlifting performance. Twenty elite male powerlifters (including four world and three US national champions) volunteered for this study. FFM, skeletal muscle distribution (muscle thickness at 13 anatomical sites), and isolated muscle thickness and fascicle pennation angle (PAN) of the triceps long-head (TL), vastus lateralis, and gastrocnemius medialis (MG) muscles were measured with B-mode ultrasound. Fascicle length (FAL) was calculated. Best lifting performance in the bench press (BP), squat lift (SQT), and dead lift (DL) was recorded from competition performance. Significant correlations (P≤0.01) were observed between muscle distribution (individual muscle thickness from 13 sites) and performance of the SQT (r=0.79 to r=0.91), BP (r=0.63 to r=0.85) and DL (r=0.70 to r=0.90). Subscapular muscle thickness was the single best predictor of powerlifting performance in each lift. Performance of the SQT, BP, and DL was strongly correlated with FFM and FFM relative to standing height (r=0.86 to 0.95, P≤0.001). FAL of the triceps long head and vastus lateralis were significantly correlated with FFM (r=0.59, P≤0.01; 0.63, P≤0.01, respectively) and performance of the SQT (r=0.45; r=0.50, respectively; P≤0.05), BP (r=0.52; r=0.56, respectively; P≤0.05), and DL (r=0.56; r=0.54, respectively; P≤0.01). A significant positive correlation was observed between isolated muscle thickness and PAN for triceps long-head (r=0.64, P≤0.01) and gastrocnemius medialis (r=0.48, P≤0.05) muscles, but not for vastus lateralis (r=0.35). PAN was negatively correlated with powerlifting performance. Our results indicate that powerlifting performance is a function of FFM and, therefore, may be limited by the ability to accumulate FFM. Additionally, muscle architecture appears to play an important role in powerlifting performance in that greater fascicle lengths are associated with greater FFM accumulation and powerlifting performance.

Characteristics of sprint performance in college football players.

Brechue, WF, Mayhew, JL, and Piper, FC. Characteristics of sprint performance in college football players. J Strength Cond Res 24(5): 1169-1178, 2010-To investigate sprinting strategy, acceleration and velocity patterns were determined in college football players (n = 61) during performance of a 9.1-, 36.6-, and 54.9-m sprints. Acceleration and velocity were determined at 9.1-m intervals during each sprint. Lower-body strength and power were evaluated by 1 repetition maximum (1-RM) squat, power clean, jerk, vertical jump, standing long jump, and standing triple jump. Sprint times averaged 1.78 ± 0.11 seconds (9.1 m), 5.18 ± 0.35 seconds (36.6 m), and 7.40 ± 0.53 seconds. Acceleration peaked at 9.1 m (2.96 ± 0.44 m·s−2), was held constant at 18.3 m (3.55 ± 0.0.94 m·s−2), and was negative at 27.4 m (−1.02 ± 0.72 m·s−2). Velocity peaked at 18.3 m (8.38 ± 0.65 m·s−1) and decreased slightly, but significantly at 27.4 m (7.55 ± 0.66 m·s−1), associated with the negative acceleration. Measures of lower-body strength were significantly related to acceleration, velocity, and sprint performance only when corrected for body mass. Lower-body strength/BM and power correlated highest with 36.6-m time (rs = −0.55 to −0.80) and with acceleration (strength r = 0.67-0.49; power r = 0.73-0.81) and velocity (strength r = 0.68-0.53; power r = 0.74-0.82) at 9.1 m. Sprint times and strength per body mass were significantly lower in lineman compared with linebackers-tight ends and backs. The acceleration and velocity patterns were the same for each position group, and differences in sprint time were determined by the magnitude of acceleration and velocity at 9.1 and 18.3 m. Sprint performance in football players is determined by a rapid increase in acceleration (through 18.3 m) and a high velocity maintained throughout the sprint and is independent of position played. The best sprint performances (independent of sprint distance) appear to be related to the highest initial acceleration (through 18.3 m) and highest attained and maintained velocity. Strength relative to body mass and power appears to impact initial acceleration and velocity (through 18.3 m) in contribution to sprint performance.

Cross-Validation of the YMCA Submaximal Cycle Ergometer Test to Predict VO2max

Abstract Maximal oxygen uptake (VO2max) is an important indicator of health-risk status, specifically for coronary heart disease (Blair et al., 1989). Direct measurement of VO2max is considered to be the most accurate means of determining cardiovascular fitness level. Typically, this measurement is taken using a progressive exercise test on a treadmill or cycle ergometer. Unfortunately, this test is costly and time consuming and requires a well equipped laboratory, highly trained personnel, and for some populations medical supervision. Therefore, submaximal exercise test protocols that predict VO2max have been developed (Astrand & Rhyming, 1954; Fitchett, 1985). These tests require less equipment, time and are easily administered without highly skilled personnel.

Chemical and pharmacological properties of MK-927, a sulfonamide carbonic anhydrase inhibitor that lowers intraocular pressure by the topical route

A large number of sulfonamides have now been tested by the topical route for the lowering of intraocular pressure in the normal albino rabbit. Certain compounds with favorable balance between lipid and water solubility, and high activity against carbonic anhydrase, do lower pressure as much as 3 mmHg. MK-927, a thienothiopyrane-2-sulfonamide carrying an alkylamino group of pK 5.8, has desirable physicochemical properties: good water solubility below pH 5.8, a CHCl3/buffer ratio of 0.6 at pH 5.4, and a KI value against carbonic anhydrase of 2-7 nM, depending on assay conditions. Inhibition of CO2 hydration is non-competitive. By comparison with other candidate topically active sulfonamides, it is the most effective in terms of pressure lowering times duration of action. There are no apparent systemic effects or ocular toxicity. The concentration of drug reaching the ciliary process and aqueous humor is of the same order as that following parenteral sulfonamides, so that inhibition of the enzyme exceeds 99%. MK-927 is therefore a candidate for the clinical treatment of glaucoma.