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The aim of this study was to investigate the influence of a 4-week electromyostimulation training program on the strength of the knee extensors and the vertical jump performance of 10 basketball players. Electromyostimulation sessions were carried out 3 times weekly; each session consisted of 48 contractions. Testing was carried out before and after the electromyostimulation training program (week 4) and once more after 4 weeks of normal basketball training (week 8). At week 4, isokinetic strength increased significantly (p < 0.05) at eccentric and high concentric velocities (between 180 and 360 x s(-1)); this was not the case for low concentric velocities (60 and 120 degrees x s(-1)). Electromyostimulation training increased also isometric strength at the two angles adjacent to the training angle (p < 0.01). Squat jump increased significantly by 14% at week 4 (p < 0.01), whereas counter movement-jump showed no change. At week 8, gains in isokinetic, isometric strength and squat-jump performance were maintained and the counter movement jump performance increased significantly by 17% (p<0.01). Electromyostimulation as part of a short strength-training program enhanced knee extensor strength and squat jump performance of basketball players.
BACKGROUND AND PURPOSE: To evaluate the efficacy of supervised high-intensity progressive resistance training (PRT) on lower extremity strength, function, and disability in older, long-term stroke survivors. METHODS: Forty-two volunteers aged 50 years and above, 6 months to 6 years after a single mild to moderate stroke, were randomized into either a control group of upper extremity stretching or a PRT group that received a 12-week supervised high-intensity resistance training program consisting of bilateral leg press (LP), unilateral paretic and nonparetic knee extension (KE), ankle dorsiflexion (DF), and plantarflexion (PF) exercises. Functional performance was assessed using the 6-minute walk, stair-climb time, repeated chair-rise time, and habitual and maximal gait velocities. Self-reported changes in function and disability were evaluated using the Late Life Function and Disability Instrument (LLFDI). RESULTS: Single-repetition maximum strength significantly improved in the PRT group for LP (16.2%), paretic KE (31.4%), and nonparetic KE (38.2%) with no change in the control group. Paretic ankle DF (66.7% versus -24.0%), paretic ankle PF (35.5% versus -20.3%), and nonparetic ankle PF (14.7% versus -13.8%) significantly improved in the PRT group compared with the control. The PRT group showed significant improvement in self-reported function and disability with no change in the control. There was no significant difference between groups for any performance-based measure of function. CONCLUSIONS: High-intensity PRT improves both paretic and nonparetic lower extremity strength after stroke, and results in reductions in functional limitations and disability.
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BACKGROUND: Undernutrition is common in older people admitted to hospital, but little is known about how nutritional state changes after discharge. OBJECTIVE: This randomised controlled trial was designed to examine the effect of oral nutritional supplementation of undernourished very old people prepared to take supplements after hospital discharge following acute illness. METHODS: Participants aged>or=75 years with a BMI or=5% during an acute hospital stay were allocated at random to either oral nutritional supplementation for 8 weeks from hospital discharge or to usual care. Primary outcome was change in weight, secondary outcomes were handgrip strength and anthropometry. RESULTS: Of 198 patients eligible to participate, 136 patients (mean age 85 years) were randomised and 76/136 (56%) completed the study. Twenty percent (13/66) of the intervention group withdrew after only 2 weeks, citing intolerance of the supplements. Using intention-to-treat analysis, body weight increased by a mean of 1.6 and 2.2% in the control and intervention groups, respectively, but this between-group difference was not significant (p = 0.188). However, handgrip strength increased more (p=0.055) in the intervention group (13.9%) than in the control group (7.2%). CONCLUSIONS: Oral nutritional supplementation was associated with a greater increase in handgrip strength than in non-supplemented controls and this observation merits further study.
At a minimum of one year after operation, we studied 64 patients with 86 total hip arthroplasties (THA) by standard anteroposterior hip and pelvic radiographs and measurement of range of motion and of isometric abduction strength. The femoral offset correlated positively with the range of abduction (p = 0.046). Abduction strength correlated positively with both femoral offset (p = 0.0001) and the length of the abductor lever arm (p = 0.005). Using multiple regression, abduction strength correlated with height (p = 0.017), gender (p = 0.0005), range of flexion (p = 0.047) and the abductor lever arm (p = 0.060). Our findings suggest that greater femoral offset after THA allows both an increased range of abduction and greater abductor strength.
The relationship between arm strength and aerobic power (VO2 peak) was examined in 35 lower-limb disabled males. Equations related predicted VO2 peak to simple measurements of isokinetic and/or static strength. Covariance analysis (ANCOVA) showed that after allowance for level of habitual activity and lesion level there was a highly significant relationship between VO2 peak and simple strength measurements (greater for isokinetic than for static data). The findings suggest that in the wheelchair-bound the extent to which arm strength is developed has more impact upon cardiovascular performance than does the anatomical level of the lesion.
Maximal voluntary strength (torque) of the flexors and extensors of the elbow was measured in 56 normal subjects and 18 hemiparetic subjects. In normal subjects the ratio of extension to flexion strength averaged 55% and did not differ significantly between sides or sexes. The ratio of maximal extensor to flexor strength on the clinically unaffected side of hemiparetic subjects was the same as that for the normal subjects but it was significantly increased on the affected side. This increase indicates that the elbow flexors were relatively more weakened than the extensors on the hemiparetic side, a conclusion contrary to conventional clinical teaching. The increase in the ratio was not the result of co-contraction of either muscle group. A possible physiological basis for the observed distribution of weakness is suggested.
The time course of strength gain with respect to the contributions of neural factors and hypertrophy was studied in seven young males and eight females during the course of an 8 week regimen of isotonic strength training. The results indicated that neural factors accounted for the larger proportion of the initial strength increment and thereafter both neural factors and hypertrophy took part in the further increase in strength, with hypertrophy becoming the dominant factor after the first 3 to 5 weeks. Our data regarding the untrained contralateral arm flexors provide further support for the concept of cross education. It was suggested that the nature of this cross education effect may entirely rest on the neural factors presumably acting at various levels of the nervous system which could result in increasing the maximal level of muscle activation.
Our purpose was to assess muscular adaptations during 6 weeks of resistance training in 36 males randomly assigned to supplementation with whey protein (W; 1.2 g/kg/day), whey protein and creatine monohydrate (WC; 0.1 g/kg/day), or placebo (P; 1.2 g/kg/day maltodextrin). Measures included lean tissue mass by dual energy x-ray absorptiometry, bench press and squat strength (1-repetition maximum), and knee extension/flexion peak torque. Lean tissue mass increased to a greater extent with training in WC compared to the other groups, and in the W compared to the P group (p < .05). Bench press strength increased to a greater extent for WC compared to W and P (p < .05). Knee extension peak torque increased with training for WC and W (p < .05), but not for P. All other measures increased to a similar extent across groups. Continued training without supplementation for an additional 6 weeks resulted in maintenance of strength and lean tissue mass in all groups. Males that supplemented with whey protein while resistance training demonstrated greater improvement in knee extension peak torque and lean tissue mass than males engaged in training alone. Males that supplemented with a combination of whey protein and creatine had greater increases in lean tissue mass and bench press than those who supplemented with only whey protein or placebo. However, not all strength measures were improved with supplementation, since subjects who supplemented with creatine and/or whey protein had similar increases in squat strength and knee flexion peak torque compared to subjects who received placebo.
PURPOSE: This study investigated the influence of different exercise types and differences in anatomical distribution of mechanical loading patterns on bone mineral density (BMD) in elite female cyclists, runners, swimmers, triathletes, and controls (N = 15 per group). Associations between leg strength and BMD were also examined. METHODS: Areal BMD (g x cm(-2)) was assessed by duel-energy x-ray absorptiometry (DXA) (total body (TB), lumbar spine (LS), femoral neck (FN), legs, and arms). Right knee flexion and extension strength was measured using a Cybex Norm isokinetic dynamometer at 60 degrees x s(-1). RESULTS: Runners had significantly higher unadjusted TB, LS, FN, and leg BMD than controls (P < 0.05); higher TB, FN, and leg BMD than swimmers (P < 0.05); and greater leg BMD than cyclists (P < 0.05). Absolute knee extension strength was significantly (P < 0.01) correlated (0.33 < or = r < or = 0.44) with TB, FN, LS, and leg BMD for all groups combined. Weaker but still significant correlations (0.28 < or = r < or = 0.33) existed for normalized (per leg lean tissue mass) knee extension strength and all BMD sites, except FN BMD. There were no significant correlations between absolute or normalized knee flexion strength and any of the BMD variables. Absolute knee extension strength was entered as the second independent predictor for LS and leg BMD in stepwise multiple linear regression analysis (MLRA), accounting for increments of 4% and 12%, respectively, in total explained variation. CONCLUSION: We conclude that running, a weight bearing exercise, is associated with larger site-specific BMD than swimming or cycling, that the generalized anatomical distribution of loads in triathlon appears not to significantly enhance total body BMD status, and that knee extension strength is only a weak correlate and independent predictor of BMD in adolescent females.
Walking speed and isokinetic strength of knee extension were examined in 18 hemiparetic stroke patients prior to, and 4 and 8 weeks after gait training. Although increase of the walking speed did not coincide with that of the isokinetic strength of the affected and non-affected sides, regression analyses revealed that the strength of the affected side was the primary determinant of the walking speed and the variance explained by it gradually increased with a period of the training.
The sniff nasal inspiratory pressure (SNIP) consists in the measurement of pressure through an occluded nostril during sniffs performed through the controlateral nostril. It is an accurate and noninvasive approximation of esophageal pressure swing during sniff maneuvers. However SNIP can underestimate esophageal pressure swing in subjects with nasal obstruction, patients with chronic obstructive pulmonary disease and severe neuromuscular patients. Nevertheless, since SNIP maneuver has predicted normal values, is noninvasive and is easier to perform than maximal inspiratory pressure (MIP) maneuver, it could be considered as the first simple test to use in order to assess inspiratory muscle weakness. In addition, because it is as reproducible as MIP, it can be suitable to follow inspiratory muscle function in chronic neuromuscular patients. Because, of the important limit of agreement between SNIP and MIP, these two methods are not interchangeable but complementary.
The static muscular strength of the back extensors, arm flexors and hand grip were measured on industrial workers (463 men and 139 women) involved in physically demanding jobs. No significant differences in strength were found among workers on different jobs. However, strength differences were evident with respect to age and sex; women were about 60 percent as strong as men, and men below 31 years of age were stronger than men above this age.
OBJECTIVE: To determine the relationship of previous lower extremity (LE) injury and/or low back pain (LBP) on hip abduction and extension strength. DESIGN: Cohort study of college athletes at time of preparticipation screening physical. SETTING: An NCAA Division I college. PARTICIPANTS: Two hundred ten college athletes (140 males and 70 females) from an NCAA Division I school. MAIN OUTCOME MEASURES: Mean and maximal hip abduction and extension strengths were recorded using a specially designed dynamometer anchoring station. Previous injury to the LE or LBP in the past year was recorded via personal interview at the time of screening and verified by review of previous injury records. RESULTS: A significant difference in side-to-side symmetry of maximum hip extension strength was observed in female subjects who reported LE injury or LBP as compared to those who did not. Side-to-side difference in hip strength, however, did not differ between male athletes, regardless of reported LE injury or LBP status. CONCLUSION: Female athletes appear to have a differing response of the proximal hip musculature to LE injury or LBP, as compared with their male counterparts. Research is under way to further validate these findings. CLINICAL RELEVANCE: This study provides some reasoning to support the screening of hip strength during the preparticipation physical, as it may be important in the prevention of LE injury and LBP in collegiate athletes.
The purpose of this study was to evaluate isokinetic strength measurement in ankle joint. The study was divided into three parts. A comparison of dorsal and plantar flexion with and without consideration to the biomechanical circumstances was done. The series comprised 15 men and 10 women. A comparison of strength measurements of dorsal flexion with and without fixation of the upper trunk. The series consisted of 10 men. A reference series for dorsal and plantar flexion comprising 15 men (mean age = 34 +/- 9 yr) was used for comparison. Strength was tested at 0 degree, 15 degrees, 30 degrees, 60 degrees, 120 degrees, 180, and 240 degrees/s. The readings made without biomechanical adjustment were significantly higher than connected readings. Mean difference at 30 degrees/s was 8.4 +/- 7.1 Nm for dorsal flexion and 18 +/- 3.1 Nm for plantar flexion. The torque values were significantly higher when the upper trunk was not immobilized, and higher standard deviations were obtained. The left (viz. dominant) leg produced significantly higher muscle torque at all velocities for plantar flexors and at all but 180 degrees and 240 degrees/s for dorsal flexors. The regression coefficient was used as a measure of peak torque velocity relation, the coefficient was -0.50 +/- 0.16 for plantar flexion and -0.22 +/- 0.06 for dorsal flexion.