Charles P. Lambert

Muscle strength and fatigue during isokinetic exercise in individuals with multiple sclerosis.

PURPOSE To compare muscle strength and muscle fatigue of the knee extensors and flexors in individuals with multiple sclerosis (MS) and non-MS control subjects and to evaluate the reliability of muscle strength and muscle fatigue testing in these individuals. METHODS Thirty individuals (13 women and 2 men for both MS and control groups), age (mean +/- SD) 38.8 +/- 10 for MS and 33.1 +/- 7.6 yr for controls, participated in this investigation. Peak torque was measured on two occasions separated by approximately 7 d at 30, 60, 90, 120, 180 degrees.s(-1) with 2 min of recovery between each bout. The nondominant leg was tested followed by the dominant leg after 10 min of recovery. Subjects then performed three bouts of 30 flexions and extensions of the dominant leg at 180 degrees.s(-1) with 1 min of recovery between bouts. RESULTS The reliability of muscle torque was very high for individuals with MS (only 1 of 20 measurements with an ICC below 0.900). Total work was also highly reliable for MS, but the Fatigue Index (work during the last 15 contractions/work during the first 15 contractions) x 100 was not. Peak torque adjusted for age, body mass, and fat free mass (measured by whole body plethysmography; the Bod Pod; Life Measurement Instruments; Concord, CA) was significantly greater for controls than for MS for three of four lower body muscle groups tested. For the muscle fatigue test (3 bouts of 30 knee extensions and flexions at 180 degrees.s(-1)), the Fatigue Index was greater (less fatigue) for the knee extensors for controls than MS for the third bout. For flexion, the Fatigue Index was greater for controls than MS over the three bouts (group effect). Total work was significantly greater for controls than MS for the flexors (group effect) and approached significance for the extensors. CONCLUSIONS Individuals with MS were weaker than controls when data were adjusted for age, body mass, and fat free mass. This latter finding (force relative to age and fat free mass) suggests that there is a reduced ability to activate muscle mass in MS and/or the muscle mass of individuals with MS is of lower quality (i.e., reduced force/unit muscle mass) than controls.

Macronutrient considerations for the sport of bodybuilding.

Participants in the sport of bodybuilding are judged by appearance rather than performance. In this respect, increased muscle size and definition are critical elements of success. The purpose of this review is to evaluate the literature and provide recommendations regarding macronutrient intake during both ‘off-season’ and ‘pre-contest’ phases. Body builders attempt to increase muscle mass during the off-season (no competitive events), which may be the great majority of the year. During the off-season, it is advantageous for the bodybuilder to be in positive energy balance so that extra energy is available for muscle anabolism. Additionally, during the off-season, adequate protein must be available to provide amino acids for protein synthesis. For 6–12 weeks prior to competition, body builders attempt to retain muscle mass and reduce body fat to very low levels. During the pre-contest phase, the bodybuilder should be in negative energy balance so that body fat can be oxidised. Furthermore, during the pre-contest phase, protein intake must be adequate to maintain muscle mass. There is evidence that a relatively high protein intake (~30% of energy intake) will reduce lean mass loss relative to a lower protein intake (~15% of energy intake) during energy restriction. The higher protein intake will also provide a relatively large thermic effect that may aid in reducing body fat. In both the off-season and pre-contest phases, adequate dietary carbohydrate should be ingested (55–60% of total energy intake) so that training intensity can be maintained. Excess dietary saturated fat can exacerbate coronary artery disease; however, low-fat diets result in a reduction in circulating testosterone. Thus, we suggest dietary fats comprise 15–20% of the body builders’ off-season and pre-contest diets.Consumption of protein/amino acids and carbohydrate immediately before and after training sessions may augment protein synthesis, muscle glycogen resynthesis and reduce protein degradation. The optimal rate of carbohydrate ingested immediately after a training session should be 1.2 g/kg/hour at 30-minute intervals for 4 hours and the carbohydrate should be of high glycaemic index. In summary, the composition of diets for body builders should be 55–60% carbohydrate, 25–30% protein and 15–20% of fat, for both the off-season and pre-contest phases. During the off-season the diet should be slightly hyperenergetic (~15% increase in energy intake) and during the pre-contest phase the diet should be hypoenergetic (~15% decrease in energy intake).

Ibuprofen and Acetaminophen: Effect on Muscle Inflammation after Eccentric Exercise

PURPOSE We examined the influence of ibuprofen and acetaminophen on muscle neutrophil and macrophage concentrations after novel eccentric contractions. METHODS Twenty-four males (25 +/- 3 yr) were divided into three groups that received the maximal over-the-counter dose of either ibuprofen (1200 mg x d-1), acetaminophen (4000 mg x d-1), or a placebo after eccentric contractions of the knee extensors. Biopsies from the vastus lateralis were taken before and 24 h after exercise. Inflammatory cells were quantified in muscle cross-sections using immunohistochemistry. RESULTS Macrophage concentrations were elevated by 1.5- to 2.5-fold (P < 0.05) at 24 h postexercise relative to preexercise concentrations, whereas neutrophil concentrations were not significantly elevated. Muscle inflammatory cell concentrations were unaffected by treatment with ibuprofen or acetaminophen when compared with placebo. CONCLUSIONS Maximal over-the-counter doses of ibuprofen or acetaminophen, when administered therapeutically, do not affect muscle concentrations of neutrophils or macrophages 24 h after a novel bout of eccentric contractions.

Fatigue during high-intensity intermittent exercise: application to bodybuilding.

AbstractResistance exercise is an activity performed by individuals interested in competition, those who wish to improve muscle mass and strength for other sports, and for individuals interested in improving their strength and physical appearance. In this review we present information suggesting that phosphocreatine depletion, intramuscular acidosis and carbohydrate depletion are all potential causes of the fatigue during resistance exercise. In addition, recommendations are provided for nutritional interventions, which might delay muscle fatigue during this type of activity.

Titin and nebulin content in human skeletal muscle following eccentric resistance exercise.

We measured titin and nebulin content in muscle biopsies from the vastus lateralis before and 24 h after one bout of high‐intensity eccentric knee extensor resistance exercise in seven men (26 ± 3 years). Titin and nebulin content were significantly (P < 0.05) reduced after exercise by 30 and 15%, respectively. These results suggest that the structural components of the myofibrillar apparatus are degraded following high‐intensity eccentric resistance exercise in humans. Loss of these proteins may have important implications for the mechanisms regulating the adaptive response of skeletal muscle to resistance exercise.

Effect of 4 wk of deep water run training on running performance.

The purpose of this study was to determine whether trained competitive runners could maintain on-land running performance using 4 wk of deep water run training instead of on-land training. Eleven well-trained competitive runners (10 males, 1 female; ages, 32.5 +/- 5.4 yr; height, 179.8 +/- 9.3 cm; weight, 70.4 +/- 6.7 kg (mean +/- SD)) trained exclusively using deep water run training for 4 wk. Subjects trained 5-6 d.wk-1 for a total of 20-24 sessions (mean +/- SD, 22 +/- 1.5 sessions). Instruction and practice sessions were conducted prior to the training period. Before and after the deep water run training, subjects completed a 5-km race on the treadmill using a computer based system, a submaximal run at the same absolute workload to assess running economy, and a combined lactate threshold and maximal oxygen consumption test. No significant differences were found for (mean +/- SEM): 5-km run time (pre, 1142.7 +/- 39.5 s; post, 1149.8 +/- 36.9 s; P = 0.28), submaximal oxygen consumption (pre 44.8 +/- 1.2 mL.kg-1.min-1; post, 45.3 +/- 1.5 mL.kg-1.min-1; P = 0.47), lactate threshold running velocity (pre, 249.1 +/- 0.9 m.min-1; post, 253.6 +/- 6.3 m.min-1; P = 0.44), or maximal oxygen consumption (pre, 63.4 +/- 1.3 mL.kg-1.min-1; post, 62.2 +/- 1.3 mL.kg-1.min-1; P = 0.11). Also no differences were found among Global Mood State pre-training, each week during training, and post-training. Competitive distance runners maintained running performance using 4 wk of deep water run training as a replacement for on-land training.

Effects of hormone replacement therapy on selected indices of immune function in postmenopausal women

The purpose of this study was to examine the effects of long-term hormone replacement therapy (HRT) on selected indices of resting immune function in postmenopausal women. Postmenopausal women aged 54–66 were divided into two groups, those taking HRT (n = 17) and controls (n = 19). Blood samples were obtained and analyzed for mononuclear cell numbers, lymphocyte proliferation (LP) and natural cell-mediated cytotoxicity (NCMC). There were no significant differences between groups for mononuclear cell numbers. LP was significantly higher for HRT, while NCMC was significantly lower for HRT. HRT is currently being prescribed to postmenopausal women for prevention of a variety of medical conditions including osteoporosis, cardiovascular disease, stroke, and Alzheimer’s disease yet HRT is often associated with altered immune parameters. In this study, women taking HRT had increased lymphocyte blastogenesis and decreased NCMC compared to controls.

Adaptations to Aerobic and Resistance Exercise in the Elderly

Maximal aerobic exercise capacity (VO2 max) is the product of maximal cardiac output (Q) and the maximal arteriovenous oxygen difference (A-VO2diff) (VO2 = Q X AVO2). Generally speaking, cardiac output represents oxygen delivery to the working muscle and A-VO2 difference is oxygen extraction at the muscle tissue level. Maximal Q is product of stroke volume (SV), the amount of blood pumped per heart beat, and heart rate (HR) or the number of times the heart beats/min (Q = SV X HR). VO2 max declines ∼1%/year after the age of 25 in non-training individuals [1–3]. Thus, the VO2 max of an untrained elderly individual is significantly lower than that of an untrained young individual. However, this decline in maximal oxygen consumption is ∼0.5%/year in master athletes who participate in aerobic activities [4]. Further, Pollock et al. [5] reported that there was a non-significant 1.7% decline in VO2 max over 10.1 years in master athletes who remained competitive and maintained their training intensity while in other master athletes who continued to train but reduced their training intensity there was a significant 12.6% decline in VO2 max over the 10.1 year period. The reason for the decline in maximal aerobic capacity in sedentary individuals is likely due to 3 major factors. A decline in maximal cardiac output [6], a decline in muscle oxidative capacity due to aging and/or inactivity [7], and a decline in metabolically active muscle mass with a concomitant increase in metabolically inactive fat mass [8]. To examine the effect of the reduction in muscle mass/and increase in fat mass in the elderly on VO2 max, Proctor et al. [8] expressed VO2 max relative to appendicular muscle mass. These investigators reported that ∼50% of the decline in VO2 max with aging was accounted for by the decline in muscle mass and increase in fat mass. Thus, the other ∼50% was related to a decline in oxygen delivery and/or oxygen extraction. Other investigators have reported that the decline in fat free mass accounts for ∼35% of the decline in VO2 max [9]. It is clear that the maximal cardiac output declines with aging but whether muscle oxidative capacity (which is a major determinant of A-VO2 difference) declines with aging is a question that is presently under scientific debate. The results of early studies of aerobic exercise training in the elderly suggested that there was little adaptation in aerobic capacity [10–13]. These early studies have been criticized as a result of the exercise intensity being inadequate to stimulate adaptation. Subsequent studies with relatively high exercise intensities suggested that the magnitude of the adaptation in fitness level of elderly individuals is similar to that of younger individuals [14–18]. In a seminal study, Kohrt et al. [17] had elderly individuals (age 60–71) exercise 4 days/wk, 45 min/day for 9–12 months with exercise intensity gradually increasing from 76% of heart rate maximum to ∼83% of heart rate maximum over the training period. These investigators reported a significant improvement of VO2 max of 24%. When subjects were grouped by age (60–62, 63–66, and 67–71 years) there were no differences between groups in the improvement of VO2 max. Similar increases in VO2 max have been observed by other investigators utilizing strenuous aerobic exercise training [14–16]. Elderly women appear to adapt to exercise training with similar increases in VO2 max as elderly men. Interestingly, however, the mechanism by which elderly men and women increase their VO2 max appears to be different. Using a similar exercise training paradigm as Kohrt et al. [17], Spina et al. [19] reported that ∼66% of the improvement in VO2 max in elderly men was due to an increase in cardiac output and more specifically stroke volume. However, in elderly women these investigators reported that the improvement in VO2 max was due to an enhanced A-VO2 difference with no change in cardiac output. Spina et al. [20,21] using echocardiography, the drug atropine (which releases vagal tone) and the β-adrenergic agonist isoproterenol reported that the endurance exercise training in women had no effect on left ventricular function or left

Effects of Megestrol Acetate on Pituitary Function and End-Organ Hormone Secretion: A Post Hoc Analysis of Serum Samples from a 12-Week Study in Healthy Older Men

BACKGROUND Megestrol acetate (MA) is a synthetic progestin commonly used to promote weight gain in malnourished older individuals. In small studies, MA administration has been associated with reduced serum cortisol concentrations in patients with cancer or AIDS. The impact of MA on the pituitary secretion of adrenocorticotropic hormone (ACTH) and other hormones is unclear, and the prevalence and extent of hypocortisolemia in older individuals after MA treatment is unknown. A randomized, placebo-controlled study of the effects of testosterone (T) and resistance training (RT) on body composition after MA administration in older men has been reported previously. OBJECTIVE The purpose of this post hoc analysis was to examine the effect of 12 weeks of MA on pituitary function and end-organ hormone secretion in healthy older individuals using frozen serum samples from that study. METHODS The previous study was conducted at the Department of Geriatrics, Donald W. Reynolds Center on Aging and the General Clinical Research Center at The University of Arkansas for Medical Sciences, Little Rock, Arkansas. Healthy male volunteers aged 60 to 85 years were recruited from the center and were randomly assigned to 1 of 4 study groups: RT + T, T, RT + placebo (P), or P. Subjects enrolled in the RT groups underwent supervised upper- and lower-body strength-training exercises 3 d/wk at 80% of 1 repetition maximum. Subjects in the groups to receive T received injections of testosterone enanthate 100 mg i.m. QW for 12 weeks. Subjects receiving P were given 1-mL saline injections i.m. QW for 12 weeks. All subjects received MA 800 mg p.o. QD concurrently for 12 weeks. For the present analysis, serum concentrations of the pituitary hormones follicle-stimulating hormone (FSH), thyroid-stimulating hormone (TSH), ACTH, prolactin (PRL), and luteinizing hormone (LH), as well as the end-organ hormones estradiol (E2), cortisol, free T4, and T, were measured in samples obtained at baseline (week 0) and after 12 weeks of MA treatment. RESULTS Serum samples from 21 men (mean [SD]age, 67.0 [7.3]years; mean [SD] body mass index, 23.1 [10.4] kg/m2; mean [SD] percentage of body fat, 22.5% [8.8%]; RT + T, T, RT + P, and P groups, n = 4, 5, 6, and 6 subjects, respectively) were available from the original study. The mean percentage changes from baseline in serum pituitary hormone concentrations after 12 weeks of MA administration were as follows: TSH, -14.7%; ACTH, -89.5%; PRL, 162.2%; and LH, -49.0%; (P = 0.03, <0.001, <0.001, and <0.001, respectively). The mean (SD) percentage changes from baseline in serum end-organ hormone concentrations with MA at 12 weeks were as follows: E2, 181.6%; and cortisol, -90.8% (both, P < 0.001). In the P and RT + P groups, the mean percentage changes from baseline in T were -84% and -85%, respectively (both, P < 0.001). FSH and free T4 concentrations were not significantly changed. CONCLUSIONS This analysis of serum samples from healthy older men suggests that MA administration significantly affected the secretion of several pituitary hormones and end-organ hormone synthesis. Most notably, ACTH secretion and serum cortisol levels were statistically significantly suppressed in 20 of 21 subjects, without the development of clinically significant adrenal suppression.

Albuterol improves response to levodopa and increases skeletal muscle mass in patients with fluctuating Parkinson disease.

Animal studies indicate that &bgr;2-adrenergic receptor agonists enhance transport of levodopa across the blood–brain barrier. Preliminary studies showed improved response to levodopa in patients with Parkinson disease (PD) who were given albuterol as adjunctive therapy. &bgr;2-Adrenergic agonists may offer additional benefits to PD patients via their skeletal muscle anabolic effects, particularly those who experience decreased muscle strength and weight loss. Nondemented, fluctuating PD patients receiving levodopa but not experiencing severe dyskinesias underwent the following tests at baseline and 14 weeks after treatment with albuterol sulfate (4 mg four times a day, orally): Unified Parkinsons Disease Rating Scale motor, tapping, and stand–walk–sit tests every 30 minutes between 8 am and 5 pm; body composition analyses using whole-body plethysmography and computed tomography of the thigh; muscle strength tests; and the Parkinsons Disease Questionnaire (PDQ-39). Results were analyzed using paired t-tests (2 tailed), repeated-measures analysis of variance, and the Wilcoxon signed-rank test. Seven of 8 enrolled patients completed the study; 1 patient withdrew because of headache and anxiety. The area under the curve for all-day UPDRS motor scores improved by 9.8 ± 9.1% (mean ± standard deviation; P < 0.05) and tapping improved by 7.6 ± 8.1% (P < 0.05). The effect was more pronounced when only the response to the first levodopa dose (area under the curve, 8–11 am) was analyzed: 13.0 ± 9.8% and 9.8 ± 9.6% respectively. Thigh muscle cross-sectional area increased significantly as measured by computed tomography (5.3 ± 3.2%, P < 0.01), as did fat-free mass by whole-body plethysmography combined with total-body water determination (9.5 ± 2.9%, P < 0.05). There was no significant improvement in the stand–walk–sit test, muscle strength tests, other UPDRS sections, daily OFF time, or PDQ-39. Four patients were rated as having a mild global improvement (+1 point) on a −3 to +3-point scale, and 3 of them chose to continue albuterol beyond the termination of the study. The mean heart rate increased from 78.3 ± 9.3 beats/minute to 85.6 ± 8.7 beats/minute (P < 0.05). No laboratory abnormalities or electrocardiographic changes were induced by albuterol in any subject. This open-label pilot study suggests that albuterol increases muscle mass and improves the therapeutic response to levodopa in patients with fluctuating PD. A double-blind, placebo-controlled study is needed to confirm the effects and safety profile of &bgr;2-agonists in PD.