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The effect of caffeine on maximal oxygen uptake and vertical jump performance in male basketball players.
Tucker, MA, Hargreaves, JM, Clarke, JC, Dale, DL, Blackwell, GJ
Journal of strength and conditioning research. 2013;(2):382-7
Abstract
This study investigated whether performance enhancement from caffeine described by other researchers transfers to male basketball players. The effects of caffeine ingestion were studied in a maximal-effort test on a treadmill that was followed by a vertical-jump test. Five elite-level male basketball players completed a graded treadmill test that measured maximal oxygen uptake, blood lactate profiles, respiratory exchange ratio, and rating of perceived exertion at each 3-minute stage. After a 15-minute warm-down, the subjects performed 10 vertical rebound jumps. Each subject completed the test twice--once with a 3 mg·kg(-1) of body weight dose of caffeine and once with a placebo, with the dosage administered 60 minutes before commencement of exercise. The test was thus administered according to a double-blind protocol. No substantial trends were found between caffeine and control trials, regardless of trial order. The study showed that the specified dosage had negligible effects on the players' power and endurance performance and had no efficacy as an ergogenic aid for male basketball players.
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Combined measures of movement and force variability distinguish Parkinson's disease from essential tremor.
Poon, C, Robichaud, JA, Corcos, DM, Goldman, JG, Vaillancourt, DE
Clinical neurophysiology : official journal of the International Federation of Clinical Neurophysiology. 2011;(11):2268-75
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Abstract
OBJECTIVE To examine whether behavioral and electrophysiological measures of motor performance accurately differentiate Parkinson's disease (PD) and essential tremor (ET). METHODS Twenty-four patients (12 PD; 12 ET) performed isometric force, ballistic movements, and tremor tasks. Receiver operating characteristic (ROC) analyses were conducted on all dependent measures that were significantly different between the two patient groups. RESULTS Patients with PD were more impaired on measures of movement deceleration than ET. Patients with ET were more impaired on measures of force variability than PD. ROC analyses revealed that sensitivity and specificity were excellent when combining measures during the isometric force task (torque rise time and force variability; 92% sensitivity and 92% specificity; AUC = 0.97). When combining measures across the force and movement tasks, the ROC analysis revealed improved sensitivity and specificity (force variability and peak deceleration; 92% sensitivity and 100% specificity; AUC = 0.99). CONCLUSIONS Combining measures of force variability and movement deceleration accurately differentiate patients with PD from those with ET with high sensitivity and specificity. SIGNIFICANCE If validated in a larger sample, these measures can serve as markers to confirm the diagnosis of PD or ET and thus, enhance decision making for appropriate treatments for patients with these respective diseases.
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Physical training in institutionalized elderly people with multiple diagnoses--a controlled pilot study.
Rydwik, E, Frändin, K, Akner, G
Archives of gerontology and geriatrics. 2005;(1):29-44
Abstract
Reduction in muscle mass and physical function depends on a variety of interacting factors: age, physical activity level, nutritional state and the type and impact of disease. The aim of this study was to investigate the effect of an individualized moderate intensity physical training program on muscle strength, balance, mobility, ambulation and activities of daily living (ADL) in institutionalized elderly people aged 65 and over with multiple diagnoses. Baseline assessments consisted of strength, balance, mobility/ambulation, and ADL. Twenty-one subjects were included in the intervention program. A control group (21 subjects) was first matched in pairs according to gender, age, ADL and mobility, and then by balance, ambulation and strength. The intervention program was individualized and included strength, mobility, balance and endurance training. Follow-up measures were conducted directly after the intervention and 10 weeks later. After drop-out, 20 subjects in the intervention group and 15 subjects in the control group remained for analyses. Balance and mobility improved significantly in the intervention group while declining in the control group. This pilot study indicates that a physical training program may improve functional capacity for institutionalized elderly persons with multiple diagnoses.
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Repeated maximal eccentric actions causes long-lasting disturbances in movement control.
Bottas, R, Linnamo, V, Nicol, C, Komi, PV
European journal of applied physiology. 2005;(1-2):62-9
Abstract
This study examined acute and long-lasting effects of fatigue and muscle damage on fast and accurate elbow flexion and extension target movements (TM) with eight male students. An isokinetic machine was used to perform 100 maximal eccentric and concentric elbow flexions at 4-week intervals. Movement range was 40-170 degrees in eccentric exercise (ECCE) and 170-40 degrees in concentric exercise (CONE), with an angular velocity of 2 rad s(-1). TM was performed in sitting position with the right forearm fixed to lever arm above protractor. Subjects performed TM in horizontal plane (amplitude 60 degrees ) by visual feedback of movement from a television monitor. Surface EMG was recorded from the biceps brachii and triceps brachii muscles. TM measurements and serum creatine kinase (CK) determinations were conducted before, after, 0.5 h, 2 days, and 7 days after both exercises. Blood lactate was taken before, after, and 0.5 h after the exercises. Both ECCE and CONE led to a large decline in maximal voluntary contractions, but the recovery was slower after ECCE when it remained incomplete even until day 7 post-exercise. Lactate increased (P < 0.001) similarly after both exercises. Delayed-onset muscle soreness peaked on day 2 and CK peaked on day 7 after ECCE. Exhaustive eccentric exercise of agonistic muscles impaired the flexion TM performance, and had a long-duration modulation effect on the triphasic EMG activity pattern of flexion and extension TM. In the acute phase, the observed changes in performance and in the EMG patterns are suggested to be related to metabolic changes via III and IV muscle afferents. The delayed recovery, on the other hand, may be related to problems in the proprioceptive feedback caused by muscle damage.
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Leg-extension strength and chair-rise performance in elderly women with Parkinson's disease.
Pääsuke, M, Ereline, J, Gapeyeva, H, Joost, K, Mõttus, K, Taba, P
Journal of aging and physical activity. 2004;(4):511-24
Abstract
The lower extremity performance in elderly female patients with mild to moderate Parkinson's disease (PD; n = 12) and controls (n = 16) was compared. Isometric dynamometry and force-plate measurements were used. PD patients had lower (p < .05) bilateral (BL) maximal isometric leg-extension force (MF), BL isometric MF relative to body mass, and maximal rate of isometric force development than control participants. BL strength deficit was greater (p < .05) in PD patients than in controls. A significantly longer chair-rise time and lower maximal rate of vertical-ground-reaction-force development while rising from a chair was found in PD patients than in controls. These findings suggest that elderly women with PD have lowered voluntary isometric force-generation capacity of the leg-extensor muscles. Reduced BL leg-extension strength might contribute to the difficulty of individuals with PD to rise from a chair.
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Phosphate deposition capacity of athletes during hypokinesia, phosphate loading, and ambulation.
Zorbas, YG, Kakurin, VJ, Kuznetsov, NA, Yarullin, VL, Andreyev, ID, Charapakhin, KP
Biological trace element research. 2002;(3):211-26
Abstract
Hypokinesia (diminished movement) induces significant phosphate (P) excretion; however, little is known about the P deposition ability of the body during hypokinesia (HK). Using P loads, the aim of this study was to establish the deposition ability of the body to retain P during prolonged HK. Studies were done during a 30-d period of pre-HK and a 364-d period of HK. Forty male trained athletes aged 24.7 +/- 8.0 yr were chosen as subjects. They were equally divided into four groups: unloaded ambulatory control subjects (UACS), unloaded hypokinetic subjects (UHKS), loaded ambulatory control subjects (LACS), and loaded hypokinetic subjects (LHKS). All hypokinetic subjects were limited to an average walking distance of 0.7 km/d. Loading tests with 85.0 mg of calcium phosphate/kg body weight were performed on the LACS and LHKS. Fecal P loss, urinary calcium (Ca) and P loss, serum P, Ca, and the ionized calcium (CaI) levels increased significantly (p < or = 0.05) in the LHKS and UHKS groups when compared with the LACS and UACS groups, respectively. Serum intact parathyroid hormone (iPTH) and the 1,25-dihydroxyvitamin D3 [1,25-(OH)2 D3] levels decreased significantly (p < or = 0.05) in the LHKS and UHKS groups when compared with the LACS and UACS groups, respectively. After the P load, significant (p < or = 0.05) differences were observed between LHKS and UHKS groups regarding serum, urinary, and fecal P changes. Thus, the deposition capacity of P decreased significantly (p < or = 0.05) more in the LHKS group than in the UHKS group. The deposition of P, fecal P, urinary P and Ca, serum CaI, P, Ca, 1,25-(OH)2 D3, and iPTH changed insignificantly (p > 0.05) in control groups when compared with their baseline values. It was shown that after the P load, significant differences were observed between the loaded and unloaded hypokinetic subjects regarding serum, urinary, and fecal P values and P retention. The oral P load intensified P loss from the body. It was concluded that the higher the P intake increased the greater P loss and the lower P deposition and thus the less likely it is for the P load to benefit hypokinetic subjects.