University of Jyväskylä

About: University of Jyväskylä is a education organization based out in Jyvaskyla, Finland. It is known for research contribution in the topics: Population & Context (language use). The organization has 8066 authors who have published 25168 publications receiving 725033 citations. The organization is also known as: Jyväskylän yliopisto & Kasvatusopillinen korkeakoulu.

Coimpairments as predictors of severe walking disability in older women.

Abstract: OBJECTIVE: Severe disabilities are common among older people who have impairments in a range of physiologic systems. It is not known, however, whether the presence of multiple impairments, or coimpairments, is associated with increased risk of developing new disability. The aim of this study was to determine the combined effects of two impairments, decreased knee-extension strength and poor standing balance, on the risk of developing severe walking disability among older, moderately-to-severely disabled women who did not have severe walking disability at baseline. DESIGN: The Women's Health and Aging Study is a 3-year prospective study with 6 semi-annual follow-up data-collection rounds following the baseline. SETTING: At baseline, knee-extension strength and standing balance tests took place in the participants' homes. PARTICIPANTS: 758 women who were not severely walking disabled at baseline. MEASUREMENTS: Severe walking disability was defined as customary walking speed of <0.4 meters/second and inability to walk one quarter of a mile, or being unable to walk. RESULTS: Over the course of the study, 173 women became severely disabled in walking. The cumulative incidence of severe walking disability from the first to the sixth follow-up was: 7.8%, 12.0%, 15.1% 19.5% 21.2%, and 22.8%. In Cox proportional hazards models, both strength and balance were significant predictors of new walking disability. In the best balance category, the rates of developing severe walking disability expressed per 100 person years were 3.1, 6.1, and 5.3 in the highest- to lowest-strength tertiles. In the middle balance category, the rates were 9.6, 13.2, and 14.7, and in the poorest balance category 21.6, 12.7, and 37.1, correspondingly. The relative risk (RR) of onset of severe walking disability adjusted for age, height, weight, and race was more than five times greater in the group with poorest balance and strength (RR 5.12, 95% confidence limit [95% CI] 2.68–9.80) compared with the group with best balance and strength (the reference group). Among those who had poorest balance and best strength, the RR of severe walking disability was 3.08 (95% CI 1.33–7.14). Among those with best balance and poorest strength, the RR was 0.97 (95% CI 0.49–1.93), as compared with the reference group. CONCLUSION: The presence of coimpairments is a powerful predictor of new, severe walking disability, an underlying cause of dependence in older people. Substantial reduction in the risk of walking disability could be achieved even if interventions were successful in correcting only one of the impairments because a deficit in only one physiologic system may be compensated for by good capacity in another system.

Breakdown of high-energy phosphate compounds and lactate accumulation during short supramaximal exercise.

Abstract: Muscle ATP, creatine phosphate and lactate, and blood pH and lactate were measured in 7 male sprinters before and after running 40, 60, 80 and 100 m at maximal speed. The sprinters were divided into two groups, group 1 being sprinters who achieved a higher maximal speed (10.07 +/- 0.13 m X s-1) than group 2 (9.75 +/- 0.10 m X s-1), and who also maintained the speed for a longer time. The breakdown of high-energy phosphate stores was significantly greater for group 1 than for group 2 for all distances other than 100 m; the breakdown of creatine phosphate for group 1 was almost the same for 40 m as for 100 m. Muscle and blood lactate began to accumulate during the 40 m exercise. The accumulation of blood lactate was linear (0.55 +/- 0.02 mmol X s-1 X l-1) for all distances, and there were no differences between the groups. With 100 m sprints the end-levels of blood and muscle lactate were not high enough and the change in blood pH was not great enough for one to accept that lactate accumulation is responsible for the decrease in running speed over this distance. We concluded that in short-term maximal exercise, performance depends on the capacity for using high-energy phosphates at the beginning of the exercise, and the decrease in running speed begins when the high-energy phosphate stores are depleted and most of the energy must then be produced by glycolysis.

Forefoot strikers exhibit lower running-induced knee loading than rearfoot strikers.

Abstract: AB Purpose: Knee pain and Achilles tendinopathies are the most common complaints among runners. The differences in the running mechanics may play an important role in the pathogenesis of lower limb overuse injuries. However, the effect of a runner's foot strike pattern on the ankle and especially on the knee loading is poorly understood. The purpose of this study was to examine whether runners using a forefoot strike pattern exhibit a different lower limb loading profile than runners who use rearfoot strike pattern. Methods: Nineteen female athletes with a natural forefoot strike (FFS) pattern and pair-matched women with rearfoot strike (RFS) pattern (n = 19) underwent 3-D running analysis at 4 m[middle dot]s-1. Joint angles and moments, patellofemoral contact force and stresses, and Achilles tendon forces were analyzed and compared between groups. Results: FFS demonstrated lower patellofemoral contact force and stress compared with heel strikers (4.3 +/- 1.2 vs 5.1 +/- 1.1 body weight, P = 0.029, and 11.1 +/- 2.9 vs 13.0 +/- 2.8 MPa, P = 0.04). In addition, knee frontal plane moment was lower in the FFS compared with heel strikers (1.49 +/- 0.51 vs 1.97 +/- 0.66 N[middle dot]m[middle dot]kg-1, P =0.015). At the ankle level, FFS showed higher plantarflexor moment (3.12 +/- 0.40 vs 2.54 +/- 0.37 N[middle dot]m[middle dot]kg-1; P = 0.001) and Achilles tendon force (6.3 +/- 0.8 vs 5.1 +/- 1.3 body weight; P = 0.002) compared with RFS. Conclusions: To our knowledge, this is the first study that shows differences in patellofemoral loading and knee frontal plane moment between FFS and RFS. FFS exhibit both lower patellofemoral stress and knee frontal plane moment than RFS, which may reduce the risk of running-related knee injuries. On the other hand, parallel increase in ankle plantarflexor and Achilles tendon loading may increase risk for ankle and foot injuries