PURPOSE: To compare the effects of a 10-week training program with two different exercises -- traditional hamstring curl (HC) and Nordic hamstrings (NH), a partner exercise focusing the eccentric phase -- on muscle strength among male soccer players. METHODS: Subjects were 21 well-trained players who were randomized to NH training (n = 11) or HC training (n = 10). The programs were similar, with a gradual increase in the number of repetitions from two sets of six reps to three sets of eight to 12 reps over 4 weeks, and then increasing load during the final 6 weeks of training. Strength was measured as maximal torque on a Cybex dynamometer before and after the training period. RESULTS: In the NH group, there was an 11% increase in eccentric hamstring torque measured at 60 degrees s(-1), as well as a 7% increase in isometric hamstring strength at 90 degrees, 60 degrees and 30 degrees of knee flexion. Since there was no effect on concentric quadriceps strength, there was a significant increase in the hamstrings:quadriceps ratio from 0.89 +/- 0.12 to 0.98 +/- 0.17 (11%) in the NH group. No changes were observed in the HC group. CONCLUSION: NH training for 10 weeks more effectively develops maximal eccentric hamstring strength in well-trained soccer players than a comparable program based on traditional HC.
In the developed countries, people are living longer and the number of aged persons is growing. Knowledge on the effectiveness of rehabilitative procedures is needed and information in physical performance between men and women is scarce. An intervention study was carried out in two war veterans' rehabilitation centers in Finland to examine the effects of geriatric inpatient rehabilitation on physical performance and pain in elderly men and women. The study included 441 community-dwelling persons with a mean age of 83 years. A clinical assessment and a structured interview were carried out. Cognitive capacity was evaluated with the mini-mental state examination (MMSE). Physical performance was measured through several validated tests. Pain was measured with the visual analogy scale (VAS). The rehabilitation was carried out with the standard rehabilitation protocol. Both men and women showed a statistically significant improvement in physical performance tests. The experience of pain and disease symptoms diminished significantly in both sexes (p
Measures of knee function: International Knee Documentation Committee (IKDC) Subjective Knee Evaluation Form, Knee Injury and Osteoarthritis Outcome Score (KOOS), Knee Injury and Osteoarthritis Outcome Score Physical Function Short Form (KOOS-PS), Knee Outcome Survey Activities of Daily Living Scale (KOS-ADL), Lysholm Knee Scoring Scale, Oxford Knee Score (OKS), Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), Activity Rating Scale (ARS), and Tegner Activity Score (TAS).
The aim of this prospective study over 5 years was to examine maximal isometric strength of multiple muscle groups as a predictor of losing independence in activities of daily living (ADL). The participants were from the Nordic Research on Aging (NORA75). These analyses are restricted to 567 people who at baseline were independent in ADL and participated in strength tests, and who five years later participated in follow-up ADL assessments. Tests on maximal isometric strength of hand grip, elbow flexion, knee extension and trunk flexion and extension were done using adjustable dynamometers. For each muscle group tested, three equal groups were formed for men and women separately based on distributions of results. Those who reported being unable or needing help for eating, dressing, bathing, toileting, walking indoors or transferring from a bed or a chair were rated as ADL dependent. Of the 227 initially ADL independent men, 21 (9.3%) became dependent in ADL. In women, the figures were 30 (8.8%) of 340. Multiple logistic regression models were used to predict the risk of ADL dependence in groups based on strength tertiles. After confirming that the association of muscle strength and incident ADL-dependence was similar in men and women, both genders were included in the same analyses adjusted for body weight and height, gender and research locality. Gender specific cut-offs were used for strength tertiles. All the strength tests predicted ADL dependence, with those being in the lowest tertile having two to three times greater risks than those in the highest tertile of strength. Further adjustments for chronic diseases did not materially change the results. Strength tests could be used to identify people who are still independent in ADL but who are at increased risk of becoming dependent because of poor muscle strength, and who could reduce their risk by strengthening exercises.
BACKGROUND: Osteoporosis is a growing health problem. One of the proposed reasons for this is a more sedentary lifestyle. The aim of this study was to investigate the associations between muscle strength and total body bone mineral density (TBMD) in young adults at expected peak bone mass. METHODS: Sixty-four women and 61 men (total 125) 21 years of age were included. Handgrip strength, isokinetic knee-flexion and -extension muscle strength, TBMD, and body composition were measured. RESULTS: Univariate regression analyses showed that knee flexion and extension explained almost 30% of the variation in TBMD in women, whereas handgrip strength was not associated with TBMD. In men, no correlation between any measures of muscle strength and TBMD was evident. Stepwise regression analysis showed that knee-flexion and -extension muscle strength in women were associated with TBMD, R2=0.27. In men, lean body mass, fat mass, weight, and height were predictors for TBMD, R2=0.43, whereas muscle strength did not affect the prediction of TBMD. CONCLUSIONS: Muscle strength at weight-bearing sites is related to TBMD in women, whereas body composition is related to TBMD in men. The association of lower limb strength on TBMD only in young women indicates a gender difference.
Comment In: Scand J Med Sci Sports. 2004 Feb;14(1):114971423
The isometric extension and flexion strength of the right knee was investigated in 396 men and 537 women. The probands were randomly selected from the National Population Records, either from the city of Malmö, Sweden, or from a typical agricultural region 60km outside the city. Both the extension and the flexion strength decreased with age in both groups. Between 50 years and 80 years of age the decrease was almost 40%. The urban probands had significantly lower muscle strength in both sexes. The difference was most pronounced for the knee extension strength. Also, the flexion strength was less in the urban population, the difference significant only in octogenarians.
This study examined the relative contribution of genetic and environmental effects on maximal leg extensor power and also investigated whether leg extensor power and maximum voluntary isometric knee extensor strength share a genetic component.
Muscle functions were measured as part of the Finnish Twin Study on Aging in 101 monozygotic (MZ) and 116 dizygotic (DZ) female twin pairs aged 63-76 yr. Leg extensor power was measured using the Nottingham Leg Extensor Power Rig and maximum voluntary isometric knee extensor strength using an adjustable dynamometer chair. The analyses were carried out using the maximum likelihood method in Mx-program on the raw data set.
A bivariate Cholesky decomposition model showed that leg extensor power and isometric knee extensor strength shared a genetic component in common, which accounted for 32% of the total variance in leg extensor power and 48% in isometric knee extensor strength. In addition, power and strength had a nonshared environmental effect in common accounting for four percent of the variance in power and 52% in strength. Remaining variance for leg extensor power was due to trait-specific shared and nonshared environmental effects.
Observed genetic effect in common for leg extensor power and maximum voluntary isometric knee extensor strength indicated that these two traits are regulated by the same genes. However, also environmental effects have a significant role in explaining the variability in power and strength.
In all 56 tibiae from Lapps and 56 from Norwegians have been studied. These ethnic groups represent different weight bearing situations. Variables dealing with the extension in the knee joint are dealth with. The bone is mainly studied in the AP and the ML planes. The material is analyzed statistically. The distribution form is examined and the deviations from normality are found to be moderate. Chiefly positive skewness occurs. Platykurtosis is found equally often as leptokurtosis. The deviations from a standard normal distribution are not supposed to affect the results significantly. There is a non-systematic pattern of distribution. The variability is generally lower in Lapps than in Norwegians. The variability is about the same in linear and angular variables and in indices. In linear variables females and Lapps show lower mean values than males and Norwegians, respectively. Lapps show the largest indices. In linear variables, contrary to in angular variables and indices, the sex differences exceed the differences between the ethnic groups. As a rule sex differences are largest in Lapps. The variations of the tuberositas tibiae are supposed to be in particular the results of muscular forces in bone remodeling. The relationship between the habitual knee position and extension is discussed.