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Byline: Yi-Fei. Hsin, Shu-Hsin. Chen, Teng-Jen. Yu, Chung-Chi. Huang, Yen-Huey. Chen PURPOSE: Muscle atrophy and diaphragm dysfunction are common with prolonged mechanical ventilation (PMV). Electrical stimulation on peripheral muscles has [...]

Background/Objectives: The purpose of this study was to evaluate the independent and combined associations of moderate-to-vigorous physical activity (MVPA), leisure time sedentary behavior and daily protein consumption on lower extremity muscular strength and lean mass. Subjects/Methods: Data from the 1999-2002 NHANES were utilized (N=1080 adults 50-85 y). Leg lean mass was estimated from dual-energy x-ray absorptiometry scans. Knee extensor strength was assessed objectively using the Kin Com MP dynamometer. MVPA and leisure time sedentary behavior were assessed via questionnaire, with the number of meals per day of [greater-than or slanted equal to]30 g of protein per meal assessed via a 'multiple pass' 24-h dietary interview. Results: Meeting MVPA guidelines ([beta]=16.3, P=0.02) and consuming at least two meals per day of [greater-than or slanted equal to]30 g of protein per meal ([beta]=28.8, P=0.02) were independently associated with greater lower extremity strength, whereas sedentary behavior was not ([beta]=11.6, P=0.23). Finally, there was no evidence of a three-way interaction of these behaviors on lower extremity strength ([beta]=-8.7; P=0.70) or lower extremity lean mass ([beta]=144.5; P=0.75). Conclusions: Although MVPA and frequency of protein consumption of [greater-than or slanted equal to]30 g of protein per meal were independently associated with lower extremity lean mass and strength, the results of the present study do not provide evidence to suggest that there is a three-way interplay between MVPA, sedentary behavior and frequency of protein consumption [greater-than or slanted equal to]30 g of protein per meal on lower extremity lean mass and strength., Author(s): P D Loprinzi [sup.1] , J P Loenneke [sup.2] , D L Hamilton [sup.3] Author Affiliations: (1) Department of Health, Exercise Science, and Recreation Management, Physical Activity Epidemiology Laboratory, [...]

BACKGROUND/OBJECTIVES: The association of bioimpedance phase angle (PA), as a measure of nutritional status, with muscle function, health-related quality of life (QoL) and subsequent clinical outcomes in maintenance hemodialysis (MHD) patients. SUBJECTS/METHODS: A 2-year prospective observational study on 250 MHD outpatients (36.8% women) with a mean age of 68.7 ± 13.6 years. Prospective all-cause and cardiovascular (CV) hospitalization and mortality, malnutrition- inflammation score (MIS), handgrip strength (HGS), bioimpedance and short form 36 (SF-36) QoL scores were the study's measurements. RESULTS: Across the three PA tertile groups, HGS was incrementally higher in the higher PA tertiles (P < 0.001), maintaining this order in both male (r=0.38, P < 0.001) and female patients (r =0.36, P < 0.001). Better self-reported QoL was noted with higher PA values. This trend was prominent in total score (P < 0.001), mental health (P =0.005) and physical health (P < 0.001) dimensions, and in most of the SF-36 scales. For each 1° increase in baseline PA, the first hospitalization hazard ratio (HR) was 0.79 (95% confidence interval (CI), 0.68-0.91) and first CV event HR was 0.70 (95% CI, 0.52-0.95);all-cause death HR was 0.63 (95% CI, 0.48-0.81) and CV death HR was 0.64 (95% CI, 0.44-0.91). Associations between PA and morbidity risk continued to be significant after adjustments for various confounders, but the association between PA and mortality risk was abolished after adding MIS to the multivariable model. CONCLUSIONS: For the MHD population, PA emerged as a useful predictor for impaired muscle function, health-related Qol, upcoming hospitalizations and mortality. European Journal of Clinical Nutrition (2014) 68, 683-689; doi:10.1038/ejcn.2014.67; published online 16 April 2014, INTRODUCTION Bioimpedance phase angle (PA) is attracting increasing interest. However, studies on the utility of this parameter are relatively scarce. There is evidence of PA's prognostic ability in maintenance hemodialysis [...]

High concentrations of caffeine and taurine are key constituents of many ergogenic supplements ingested acutely to provide legal enhancements in athlete performance. Despite this, there is little evidence supporting the claims for the performance-enhancing effects of acute taurine supplementation. In-vitro models have demonstrated that a caffeine- induced muscle contracture can be further potentiated when combined with a high concentration of taurine. However, the high concentrations of caffeine used in previous research would be toxic for human consumption. Therefore, this study aimed to investigate whether a physiological dose of caffeine and taurine would directly potentiate skeletal muscle performance. Isolated mouse soleus muscle was used to examine the effects of physiological taurine (TAU), caffeine (CAF), and taurine- caffeine combined (TC) on (i) acute muscle power output; (ii) time to fatigue; and (iii) recovery from fatigue, compared with the untreated controls (CON). Treatment with TAU failed to elicit any significant difference in the measured parameters. Treatment with TC resulted in a significant increase in acute muscle power output and faster time to fatigue. The ergogenic benefit posed by TC was not different from the effects of caffeine alone, suggesting no acute ergogenic benefit of taurine. Key words: ergogenic aid, force, skeletal muscle, work loop. De fortes concentrations de cafeine et de taurine sont les constituantes cles de plusieurs supplements ergogenes ingeres de maniere aigue afin d'obtenir une amelioration legale de la performance sportive. Malgre cela, il n'existe que peu de preuves des effets de la taurine sur l'amelioration de la performance. Des modeles in vitro ont demontre que la cafeine induisait une contraction musculaire qui pouvait etre renforcee lorsqu'une forte concentration de taurine etait ajoutee. Cependant, la concentration elevee de cafeine utilisee lors de la recherche precedente serait toxique pour consommation humaine. En consequence, l'etude presente vise a examiner l'effet direct de doses physiologiques de cafeine et de taurine sur la potentialisation de la performance du muscle squelettique. Le muscle soleaire de souris isole a ete utilise afin d'examiner les effets de doses physiologiques de taurine (TAU), de cafeine (CAF) et de la combinaison des deux (TC) sur : (i) la puissance aigue fournie par le muscle, (ii) le temps jusqu'a la fatigue, et (iii) la recuperation de la fatigue, comparativement aux controles non traites (CON). Le traitement a la TAU ne parvenait pas a montrer quelque difference sur les parametres mesures. Le traitement a la TC resultait en une augmentation significative de la puissance aigue fournie par le muscle et en un temps jusqu'a la fatigue plus rapide. Le benefice ergogene du TC n'etait pas different des effets de la cafeine seule, ce qui suggere qu'aucun effet ergogene aigu n'est exerce par la taurine. [Traduit par la Redaction] Mots-cles: assistance ergogene, force, muscle squelettique, boucle de travail., Introduction The ability (ergogenic effect) of energy drinks to legally enhance sporting performance is largely attributed to their high concentrations of caffeine, owing to the corresponding wealth of evidence demonstrating [...]

Gonzalez-Badillo, JJ and Marques, MC. Relationship between kinematic factors and countermovement jump height in trained track and field athletes. J Strength Cond Res 24(12): 3443-3447, 2010--Countermovement jump (CMJ) has been extensively used in training, yet kinematic data for a large sample of trained athletes are limited. The aim of this study was to determine the relationship between kinematic factors of CMJ height in a large sample of trained track and field athletes. Forty-eight adult athletes performed 3 maximal CMJ-weighted jumps while ground reaction forces were sampled using a force platform synchronized with a linear transducer. The CMJ height presented significant relations with both eccentric (descending) and concentric (ascending) phases. In addition, strong correlations were observed between CMJ performance and the peak power produced during the concentric phase (r = 0.812-0.851) and with the average power generated in the same phase (r = 0.829-0.870). Finally, maximal negative velocity was low to moderate in its association with CMJ performance (r = 0.57-0.65). The present data contribute important knowledge concerning determinant factors of vertical jump performance that have not been analyzed in trained athletes. As predictors, it is important to observe high values of correlation between the force produced during the concentric and eccentric phases with the height of all the CMJ trials. In this way, our study confirms previous findings in which peak power was shown to be the best predictor of CMJ height. Nevertheless, the moderate but significant predictive value of negative velocity was even more noticeable. KEY WORDS power, force, impulse, negative velocity

Schoenfeld, BJ. Squatting kinematics and kinetics and their application to exercise performance. J Strength Cond Res 24(12): 3497-3506, 2010--The squat is one of the most frequently used exercises in the field of strength and conditioning. Considering the complexity of the exercise and the many variables related to performance, understanding squat biomechanics is of great importance for both achieving optimal muscular development as well as reducing the prospect of a training-related injury. Therefore, the purpose of this article is 2-fold: first, to examine kinematics and kinetics of the dynamic squat with respect to the ankle, knee, hip and spinal joints and, second, to provide recommendations based on these biomechanical factors for optimizing exercise performance. KEY WORDS squat, biomechanics, kinetics, kinematics

Taliep, MS, Prim, SK, and Gray, J. Upper body muscle strength and batting performance in cricket batsmen. J Strength Cond Res 24(12): 3484-3487, 2010--The aim of this study was to determine if upper body muscle strength (as measured by the 1 repetition maximum bench press) was associated with cricket batting performance. Cricket batting performance was defined by the maximum hitting distance during a batting task and batting average and strike rate during 1-Day and Twenty/20 (T/20) matches. Eighteen, provincial level, elite cricket batsmen participated in the study. Upper body muscle strength was found to be positively correlated with maximum hitting distance (p = 0.0052). There were no significant correlations between upper body strength, batting average, and strike rate for both the 1-Day and T/20 matches. The results of this study have implications for coaches choosing a particular batting line-up. Batsmen who have stronger upper bodies could be favored to bat when a match situation requires them to hit powerful strokes resulting in boundaries. However, coaches cannot use upper body strength as a predictor of overall batting performance in 1-Day or T/20 matches. KEY WORDS powers, skill, training, fitness, elite

Perroni, F, Tessitore, A, Cortis, C, Lupo, C, D'Artibale, E, Cignitti, L, and Capranica, L. Energy cost and energy sources during a simulated firefighting activity. J Strength Cond Res 24(12): 3457-3463, 2010--This study aimed to 1) analyze the energy requirement ([??][O.sub.2]eq) and the contribution of the aerobic ([??][O.sub.2]ex), anaerobic alactic ([??][O.sub.2]al), and anaerobic lactic ([??][O.sub.2]2la--) energy sources of a simulated intervention; 2) ascertain differences in mean [??][O.sub.2] and heart rate (HR) during firefighting tasks; and 3) verify the relationship between time of job completion and the fitness level of firefighters. Twenty Italian firefighters (age = 32 [+ or -] 6 yr, [??][O.sub.2]peak = 43.1 [+ or -] 4.9 mL x [kg.sup.-1] x [min.sup.-1]) performed 4 consecutive tasks (i.e., child rescue; 250-m run; find an exit; 250-m run) that required a [??][O.sub.2]eq of 406.26 [+ or -] 73.91 mL x [kg.sup.-1] ([??][O.sub.2]ex-- 86 [+ or -] 5%; [??][O.sub.2]al = 9 [+ or -] 3%; [??][O.sub.2]la- = 5 [+ or -] 3%). After 30 minutes, the recovery HR (108 [+ or -] 15 beats x [min.sup.-1]) and [??][O.sub.2] (8.86-+2.67mL x [kg.sup.-1] x [min.sup.-1]) were higher (p < 0.0001) than basal values (HR = 66 [+ or -] 8 beats x [min.sup.-1]; [??][O.sub.2] = 4.57 [+ or -] 1.07 mL x [kg.sup.-1] x [min.sup.-1]), indicating that passive recovery is insufficient in reducing the cardiovascular and thermoregulatory strain of the previous workload. Differences (p < 0.001) between tasks emerged for mean [??][O.sub.2] and HR, with a lack of significant correlation between the time of job completion and the firefighters' aerobic fitness. These findings indicate that unpredictable working conditions highly challenge expert firefighters who need adequate fitness levels to meet the requirements of their work. Practically, to enhance the fitness level of firefighters, specific interval training programs should include a wide variety of tasks requiring different intensities and decision-making strategies. KEY WORDS aerobic metabolism, anaerobic alactic metabolism, anaerobic lactic metabolism, job performance

Tse, MA, McManus, AM, and Masters, RS. Trunk muscle endurance tests: effect of trunk posture on test outcome. J Strength Cond Res 24(12): 3464-3470, 2010--The objective of this study was to investigate the effect of different trunk postures during the abdominal flexor test on isometric endurance holding times and surface electromyographic (EMG) activity of contributing trunk flexor and extensor muscles in 16 healthy college-age male rowers (age, 22.0 [+ or -] 1.55 years; height, 179.1 [+ or -] 5.47 cm; weight, 68.0 [+ or -] 4.18 kg) with a minimum of 12 months rowing experience. Subjects performed 2 maximal effort abdominal flexor tests, 1 held with correct posture and the other with a slightly flexed incorrect trunk posture. Maximum holding time was assessed for each posture while EMG muscle activity was recorded for the external oblique, rectus abdominis, internal oblique, rectus femoris, and lumbar erector spinae muscles. Mean maximal holding time for the incorrectly positioned abdominal flexor test was significantly longer than for the correct position (p < 0.05). EMG activity during the first and last 20% of a time normalized comparison showed significantly lower muscle activity during the incorrect trunk posture in all muscles investigated (p < 0.05). There were no significant differences (p > 0.05) in muscle activity when comparing an equivalent time period at the actual termination of each of the 2 abdominal flexor tests. Although minor variations in trunk posture seem to be acceptable in practice of this isometric abdominal flexor test, the present data indicate that minor lumbar kyphosis deviating away from the correct abdominal flexor test posture can significantly skew test reliability, resulting in longer endurance holding times and relatively lower muscle activity of the trunk muscles. KEY WORDS exercise, electromyography, trunk endurance, muscle fatigue, spine

Reiman, MP, Peintner, AM, Boehner, AL, Cameron, CN, Murphy, JR, and Carter, JW. Effects of dynamic warm-up with and without a weighted vest on lower extremity power performance of high school male athletes. J Strength Cond Res 24(12): 3387-3395, 2010--This study examined lower extremity power performance, using the Margaria-Kalamen Power Test, after a dynamic warm-up with (resisted) and without (nonresisted) a weighted vest. Sixteen (n = 16) high school male football players, ages 14-18 years, participated in 2 randomly ordered testing sessions. One session involved performing the team's standard dynamic warm-up while wearing a vest weighted at 5% of the individual athlete's body weight before performing 3 trials of the Margaria-Kalamen Power Test. The second session involved performing the same dynamic warm-up without wearing a weighted vest before performing 3 trials of the Margaria-Kalamen Power Test. The warm-up performed by the athletes consisted of various lower extremity dynamic movements over a 5-minute period. No significant difference was found in power performance between the resisted and nonresisted dynamic warm-up protocols (p > 0.05). The use of a dynamic warm-up with a vest weighted at 5% of the athlete's body weight was not advantageous for increasing lower extremity power output in this study. The results of this study suggest that resisted dynamic warm-up protocols may not augment the production of power performance in high school football players. KEY WORDS anaerobic performance, resisted warm-up, football, postactivation, potentiation, Margaria-Kalamen Power Test

Reyes, GFC, Dickin, DC, Dolny, DG, and Crusat, NJK. Effects of muscular strength, exercise order, and acute whole-body vibration exposure on bat swing speed. J Strength Cond Res 24(12): 3234-3240, 2010--The purposes for this study were to investigate effects of acute whole-body vibration (WBV) exposure and exercise order on bat speed and to examine relationship between muscular strength and bat speed. All participants were recreationally trained men (n = 16; 22 [+ or -] 2 years; 181.4 [+ or -] 7.4 cm; 84.7 [+ or -] 9 kg), with previous baseball experience and were tested for 1 repetitive maximum (1RM) strength in squat and bench press. Subjects then participated in 4 randomized sessions on separate days, each consisting of 3 sets of 5 bat swings. Exercises (upper and lower body dynamic and static movements related to bat swing) with or without WBV exposure were performed after sets 1 and 2. Trials were as follows: no-exercise Control (CTRL), upper body followed by lower body exercises without WBV (Arm-Leg NOVIB), upper body followed by lower body exercises with WBV (Arm-Leg VIB), and lower body followed by upper body exercises with WBV (Leg-Arm VIB). Bat speed was recorded during each swing and averaged across sets. Statistical analyses were performed to assess differences across sets and trials. Linear regressions analyzed relationship between strength and bat speed. A significant relationship existed between bat speed and lower body strength ([r.sup.2] = 0.406, p = 0.008) but not for upper body strength. The exercise order of Arm-Leg VIB significantly increased bat speed by 2.6% (p = 0.02). Performing identical order of exercises without vibration (Arm-Leg NOVIB) significantly decreased bat speed by 2% (p = 0.039). It was concluded that adding vibration exposure to total-body exercises can provide acute enhancements in bat speed. Additionally, leg strength was shown to influence bat speed suggesting that increasing leg strength may enhance bat speed. KEY WORDS baseball performance, upper body exercise, warm-up

Background/Objectives: Although loss of fat-free mass (FFM) and reduced muscle strength are highly prevalent in chronic obstructive pulmonary disease (COPD), only few data are available on the relationships of handgrip strength (HGS) and respiratory muscle strength with body composition in such disease. In particular, we aimed to assess whether raw bioelectrical impedance (BIA) variables were independent predictors of muscle strength in COPD patients, possibly more significant than anthropometric variables and BIA-based estimates of FFM. Subjects/Methods: Two hundred and thirty-seven COPD patients (161 males and 76 females) underwent respiratory, anthropometric, BIA, HGS and respiratory muscle strength (maximum inspiratory or expiratory pressure=MIP and MEP) measurements. Bioimpedance index (BI index=height square/whole-body impedance) and phase angle (PhA) were considered as raw BIA variables. FFM was estimated using three disease-specific BIA equations. Results: In COPD patients a stronger correlation was observed between HGS and PhA compared to the ones with anthropometric variables or FFM estimates. Multiple regression analysis showed that combining BI index and PhA (plus age in male patients) accounted for 50.2% and 42.6% of the variance in HGS in male and female patients, respectively. Similarly, BI index and PhA emerged as predictors of both MIP and MEP in males, while in females MIP was related only to PhA and MEP only to BI index. Conclusions: Raw BIA variables are independent and valuable predictors of HGS and respiratory muscle strength in COPD patients. BI index and PhA could provide useful information for evaluating body composition and better assessing muscle strength and physical fitness in COPD. European Journal of Clinical Nutrition (2017) 71, 1336-1340; doi: 10.1038/ejcn.2017.147; published online 13 September 2017, Author(s): F de Blasio [1]; M G Santaniello [1]; F de Blasio [2, 3]; G Mazzarella [4]; A Bianco [3, 4]; L Lionetti [5]; F M E Franssen [6]; L [...]

Skeletal muscle constitutes [approximately equal to]40% of the human body mass, and alterations in muscle mass and strength may result in physical disability. Therefore, the elucidation of the factors responsible for muscle force development is of paramount importance. Excitation--contraction coupling (ECC) is a process during which the skeletal muscle surface membrane is depolarized, causing a transient release of calcium from the sarcoplasmic reticulum that activates the contractile proteins. The ECC machinery is complex, and the functional role of many of its protein components remains elusive. This study demonstrates that deletion of the gene encoding the sarcoplasmic reticulum protein JP45 results in decreased muscle strength in young mice. Specifically, this loss of muscle strength in JP45 knockout mice is caused by decreased functional expression of the voltage-dependent [Ca.sup.2+] channel [Ca.sub.v]1.1, which is the molecule that couples membrane depolarization and calcium release from the sarcoplasmic reticulum. These results point to JP45 as one of the molecules involved in the development or maintenance of skeletal muscle strength. calcium release | excitation-contraction coupling

Background. The loss of muscle mass is considered to be a major determinant of strength loss in aging. However, large-scale longitudinal studies examining the association between the loss of mass and strength in older adults are lacking. Methods. Three-year changes in muscle mass and strength were determined in 1880 older adults in the Health, Aging and Body Composition Study. Knee extensor strength was measured by isokinetic dynamometry. Whole body and appendicular lean and fat mass were assessed by dual-energy x-ray absorptiometry and computed tomography. Results. Both men and women lost strength, with men losing almost twice as much strength as women. Blacks lost about 28% more strength than did whites. Annualized rates of leg strength decline (3.4% in white men, 4.1% in black men, 2.6% in white women, and 3.0% in black women) were about three times greater than the rates of loss of leg lean mass (~1% per year). The loss of lean mass, as well as higher baseline strength, lower baseline leg lean mass, and older age, was independently associated with strength decline in both men and women. However, gain of lean mass was not accompanied by strength maintenance or gain ([beta] coefficients; men, -48 [+ or -] 4.61, p = .92, women, -1.68 [+ or -] 3.57, p = .64). Conclusions. Although the loss of muscle mass is associated with the decline in strength in older adults, this strength decline is much more rapid than the concomitant loss of muscle mass, suggesting a decline in muscle quality. Moreover, maintaining or gaining muscle mass does not prevent aging-associated declines in muscle strength.

Infrared-light radiation has recently and effectively been applied to solving a wide range of problems in the sport sciences. However, few investigations have focused on the potential performance-enhancing properties of near-infrared (NIR)-light stimulation, and none have examined its effects on muscle strength. As such, the purpose of this investigation was to determine the extent to which NIR light influenced the maximal isokinetic strength of the quadriceps and hamstrings. Forty-eight college students participated in the study. Four experimental conditions were created: (a) an active group with expectancy instructions, (b) an active group without expectancy instructions, (c) a placebo group with expectancy instructions, and (d) a placebo group without expectancy instructions. Individuals in active conditions were outfitted in NIR light-emitting bandages, T-shirts, and socks, whereas those in placebo conditions were outfitted in the same attire but without active NIR light. Maximal isokinetic torque values of the quadriceps and hamstrings were measured. Results indicated that the active group without expectancy instructions exhibited enhanced isokinetic strength for the hamstrings at a contractile speed of 180 [degrees] x [s.sup.-1] as compared with the placebo groups. With continued replication of our initial exploratory findings, infrared equipment might emerge as a promising means for performance enhancement. KEY WORDS. ergogenic aid, leg strength, anaerobic

Methods. Total mortality rates were examined in the Health, Aging and Body Composition (Health ABC) Study in 2292 participants (aged 70-79 years, 51.6% women, and 38.8% black). Knee extension strength was measured with isokinetic dynamometry, grip strength with isometric dynamometry. Thigh muscle area was measured by computed tomography (CT) scan, and leg and arm lean soft tissue mass were determined by dual energy x-ray absorptiometry (DXA). Both strength and muscle size were assessed as in gender-specific Cox proportional hazards models, with age, race, comorbidities, smoking status, level of physical activity, fat area by CT or fat mass by DXA, height, and markers of inflammation, including interleukin-6, C-reactive protein, and tumor necrosis factor-[alpha] considered as potential confounders. Results. There were 286 deaths over an average of 4.9 (standard deviation = 0.9) years of follow-up. Both quadriceps and grip strength were strongly related to mortality. For quadriceps strength (per standard deviation of 38 Nm), the crude hazard ratio for men was 1.51 (95% confidence interval, 1.28-1.79) and 1.65 (95% confidence interval, 1.19-2.30) for women. Muscle size, determined by either CT area or DXA regional lean mass, was not strongly related to mortality. In the models of quadriceps strength and mortality, adjustment for muscle area or regional lean mass only slightly attenuated the associations. Further adjustment for other factors also had minimal effect on the association of quadriceps strength with mortality. Associations of grip strength with mortality were similar. Conclusion. Low muscle mass did not explain the strong association of strength with mortality, demonstrating that muscle strength as a marker of muscle quality is more important than quantity in estimating mortality risk. Grip strength provided risk estimates similar to those of quadriceps strength.

Background. The objective of this study was to determine if a chronic eccentric training intervention, i.e., negative work, could limit or even reverse sarcopenia and its related impairments and functional limitations. Is high-force eccentric training tolerable by elderly people and will it result in improved muscle size, strength, balance, and fall risk? Methods. 21 frail elderly subjects (mean age, 80 years) experienced 11 weeks of lower extremity resistance training. The experimental eccentric (ECC) group (n = 11) performed negative work while exercising on a high-force eccentric ergometer. The active 'controls' performed traditional (TRAD) (n = 10) lower extremity resistance exercises (weight training). Muscle fiber cross-sectional area and strength, balance, stair descending abilities, and fall risk were assessed prior to and following this intervention. Results. All ECC subjects who started the negative work intervention completed the study and reported the training to be relatively effortless; they experienced minimal and transient muscle soreness. Both groups experienced a significant increase in muscle fiber cross-sectional area (ECC = 60%, TRAD = 41%). Only the ECC group experienced significant improvements in strength (60%), balance (7%), and stair descent (21%) abilities. The timed up and go task improved in both groups, but only the ECC group went from a high to a low fall risk. Conclusions. These data demonstrate that lower extremity resistance exercise can improve muscle structure and function in those with limited exercise tolerance. The greater strength increase following negative work training resulted in improved balance, stair descent, and fall risk only in the ECC group. Because low energy cost is coupled to high force production with eccentric exercise, this intervention may be useful for a number of patients that are otherwise unable to achieve high muscle forces with traditional resistance exercise.

Low muscle strength is associated with mortality, presumably as a result of low muscle mass (sarcopenia) and physical inactivity. Grip strength was longitudinally collected in 1071 men over a 25-year period. Muscle mass was estimated by using 24-hour creatinine excretion and physical activity values, obtained by questionnaire. Survival analysis examined the impact of grip strength and rate of change in strength on all-cause mortality over 40 years. Lower and declining strength are associated with increased mortality, independent of physical activity and muscle mass. In men

Aims: To evaluate effects of a low energy diet, with or without strength training, on blood lipid profile in obese children. Methods: Eighty two obese children were enrolled into a [...]

Background. Identification of the physiologic factors most relevant to functional independence in the elderly population is critical for the design of effective interventions. It has been suggested that muscle power may be more directly related to impaired physical performance than muscle strength in elderly persons. We tested the hypothesis that peak muscle power is closely associated with self-reported functional status in sedentary elderly community-dwelling women. Methods. We used baseline data that were collected as part of a 1-year randomized controlled clinical trial of a combined program of strength, power, and endurance training in 80 elderly women (mean age 74.8 +/- 5.0 years) with 3.2 +/- 1.9 chronic diseases, selected for baseline functional impairment and/or falls. Results. Functional status at baseline was related in univariate analyses to physiologic capacity, habitual physical activity level, neuropsychological status, and medical diagnoses. Leg power had the strongest univariate correlation to self-reported functional status (r = -.47, p < .0001) of any of the physiologic factors we tested. In a forward stepwise regression model, leg press power and habitual physical activity level were the only two factors that contributed independently to functional status (r = .64, p < .0001), accounting for 40% of the variance in functional status. Conclusions. Leg power is a strong predictor of self-reported functional status in elderly women.

Back muscle oxygenation during prolonged isometric contractions is reduced, even at contraction intensity as low as 2 percent of maximum voluntary contraction. The finding has implications for occupational conditions.

Background. Muscle weakness, low body weight, and chronic diseases are often observed in the same people; however, the association of muscle strength with mortality, independent of disease status and body weight, has not been elucidated. The aim was to assess hand grip strength as a predictor of all-cause mortality within different levels of body mass index (BMI) in initially disease-free men. Methods. Mortality was followed prospectively over 30 years. Maximal hand grip strength tests and BMI assessments were done at baseline in 1965 to 1970. The participants were 6040 healthy men aged 45 to 68 years at baseline living on Oahu, Hawaii. Results. The death rates per 1000 person years were 24.6 in those with BMI 25. For grip strength tertiles, the mortality rates were 24.8 in the lowest, 18.5 in the middle, and 14.0 in the highest third. In Cox regression models, within each tertile of grip strength, BMI showed only minimal effect on mortality. In contrast, in each category of BMI there was a gradient of decreasing mortality risk with increasing grip strength. Among those with BMI 25, the RRs were 1.39 (1.16-1.65) in the lowest, 1.27 (1.08-1.49) in the middle, and 1.14 (0.98-1.32) in the highest third of grip strength. Models were adjusted for age, education, occupation, smoking, physical activity, and body height. Conclusions. In healthy middle-aged men, long-term mortality risk was associated with grip strength at baseline, independent of BMI. The possible interpretation of the finding is that early life influences on muscle strength may have long-term implications for mortality. Additionally, higher strength itself may provide greater physiologic and functional reserve that protects against mortality.

A principle component of age-related weakness and frailty in women is sarcopenia. This decrease in skeletal muscle mass is a progressive syndrome that will affect the quality of life for elderly women by decreasing the ability to perform many activities of daily living. Strength training is known to be an effective means of increasing muscular strength and size in many populations, and can be utilized successfully to significantly improve muscle strength, muscle mass and functional mobility in elderly women up to the age of 96 years. Such exercise can minimize the syndrome of physical frailty due to decreased muscle mass and strength. Any rehabilitation or exercise program for the elderly woman would benefit from the inclusion of such a training regime. Keywords: Resistance training, sarcopenia, elderly, women, muscle strength