Increase In Knee Extension Strength Research Articles

Can we replace exercises targeted on core/hip muscles by exercises targeted on leg/foot muscles in women with patellofemoral pain? A randomized controlled trial

ObjectiveTo verify the effects of replacing exercises targeted on core/hip muscles by exercises targeted on leg/foot muscles in a rehabilitation program for patellofemoral pain (PFP). DesignRandomized Controlled Trial. ParticipantsFifty women with PFP. MethodsPFP participants were randomized into the standard rehabilitation group (SRG, n = 25) or distal exercise group (DEG, n = 25). Knee pain, patient-reported function, dynamic knee valgus and muscle strength were measured at baseline and after six and twelve weeks of the program start. ResultsSRG and DEG presented similar responses to rehabilitation (except for muscle strengthening). Knee pain reduced after 6 weeks (SRG: −37.7%, ES = 1.23; DEG: −30%, ES = 0.93) and 12 weeks (SRG: −47.4%, ES = 1.53; DEG: −43.3%, ES = 1.46). Patient-reported function improved after 6 weeks (SRG: +7.3%, ES = 0.45; DEG: +3.8%, ES = 0.22) and 12 weeks (SRG: +14.1%, ES = 0.80; DEG: +8.8%, ES = 0.50). Dynamic knee valgus reduced after 12 weeks (SRG: −29.7%, ES = 0.38; DEG: −34.5%, ES = 0.32). Both groups experienced increases in knee extension strength (SRG: +9%, ES = 0.28; DEG: +6%, ES = −0.29), but only SRG had strength gains for hip abduction (+10%, ES = 0.36) and extension (+11%, ES = 0.44). ConclusionExercises targeted on core/hip muscles can be replaced by exercises targeted on leg/foot muscles in a lower limb exercise-based rehabilitation program for women with PFP. Clinical trial registrationNCT03663595.

Effect of Community-Based Group Exercise Interventions on Standing Balance and Strength in Independent Living Older Adults.

Many interventions to improve mobility in older adults often include exercises to address underlying impairments such as strength deficits. Task-oriented exercise interventions that focus more on walking and stepping tasks that may be encountered in the community have been considered for improving mobility in older adults. The main purpose was to examine the effect of task-oriented and impairment-based group exercise interventions on standing balance and lower extremity muscle strength. This is an ancillary study to a cluster-randomized clinical trial. Participants included 107 older adults. Participants were randomized by facility to 1 of 2 different interventions, or a waitlist control group. The On the Move (OTM) task-oriented intervention consisted of warm-up, timing and coordination (stepping and walking patterns), strengthening, and stretching exercises. The standard of care impairment-based exercise intervention (STD) consisted of warm-up, strength, endurance, and stretching exercises. Postural sway and balance measures were recorded before and after the 12-week interventions. An accelerometer was used to collect postural sway for 6 different standing balance conditions. A portable load cell was used to assess lower extremity muscle strength for 3 muscle groups. The OTM group had a significant reduction in sway acceleration during most of the balance conditions over the 12-week period, whereas the STD had smaller, nonsignificant reductions. Both exercise interventions had a significant reduction in sway compared with the waitlist control group in at least 1 balance condition. The OTM and STD groups had significant increases in hip abduction strength during the intervention and the STD group also had an increase in knee extension strength. The waitlist group had a significant reduction in strength in all muscle groups during the 12-week period. Strength changes in both exercise groups were significantly different from the waitlist group but not from each other. Both exercise intervention groups had an improvement in standing balance and lower extremity strength when compared with a waitlist group that did not receive exercise. Although the exercise groups did not significantly differ from each other, the OTM exercise group showed a trend toward improvement in static standing balance conditions.

Home-based resistance training for older adults: a systematic review.

Home-based resistance exercise is commonly used for individuals who might not have access or the ability to use traditional resistance exercise. However, the extent to which home-based resistance exercise can improve both strength and functional ability has not been investigated in healthy older individuals using a systematic analysis. The current article systematically reviewed the effectiveness of home-based resistance exercise on strength and functional ability. Search engines included Academic Search Premier, CINAHL, PubMed, PsycINFO, MEDLINE, SPORTDiscus and Web of Science. A total of 649 articles were found using the key words "home-based" and "strength" and "older" or "elderly", with eight articles meeting the final criteria. The average age of the participants was 76 years, with the average duration of exercise training ranging from 8 weeks to 120 weeks. Of the eight studies, a significant increase in knee extension strength was found in five studies. Functional ability significantly improved in seven of the eight studies, with the average decrease in Timed Up & Go test being -0.8 ± 0.5 s. Three studies included greater amounts of supervised visits compared with the other five studies (∼51% vs ∼7%). The more supervised studies had significant increases in strength and functional ability. Overall, home-based resistance exercise can improve both strength and functional ability, but the improvements are generally small. The intensity of the exercises might not progress sufficiently enough to produce large improvements in strength as a result of less supervision or a lack of motivation to increase the intensity further.

Increased muscle strength improves managing in activities of daily living in fall-prone community-dwelling older women

The aim of this longitudinal study was to describe whether an increase in knee extension strength is associated with improvements in managing in activities of daily living (ADL) and in self-perceived physical condition in fall-prone community-dwelling older women. Subjects (n=417) aged ≥ 65 years belonged either to intervention or control groups in a 12-month randomized controlled fall prevention trial. Isometric muscle strength of knee extension was measured with an adjustable dynamometer chair. Managing in activities of daily living was measured with structured questions about abilities to climb stairs, walk at least 400 meters, toilet, bath, go to the sauna, do light or heavy housework, and carry heavy loads. A question of self-perceived physical condition was also asked. Positive associations were found between increased knee extension strength and an increase in walking at least 400 meters (p<0.001), carrying heavy loads (p=0.004), and climbing stairs (p=0.007), and in self perceived physical condition (p=0.005) over a 12- month follow-up. In addition, low age, non-use of a walking aid, low number of prescribed medications, and good functional balance at baseline were associated with an increase in performance of these ADL functions. An increase in knee extension strength during the 12-month follow-up was associated with improvement in some ADL functions and improvement in self-perceived physical condition during the same period in fall-prone community-dwelling women.

Proximal femoral varus rotation osteotomy in cerebral palsy: a prospective gait study.

This prospective study examined the kinematic and temporal/spatial effects of proximal femoral varus rotation osteotomy (VRO) on the gait of individuals with cerebral palsy from preoperative to 1-year postoperative status. Participants were a consecutive sample of 37 individuals (14 males, 23 females). The analysis consisted of three-dimensional kinematics, temporal/spatial measures, and functional status. A curve representing the difference between the preoperative and 12-month postoperative conditions was calculated for each joint motion. Ninety-five percent confidence intervals were calculated about the mean difference curves using a bootstrapping technique. VRO resulted in improved cosmesis and objective improvement in gait, including a statistically significant increase in hip external rotation and hip extension, a decrease in anterior pelvic tilt, and an increase in knee extension strength. The use of confidence bands to identify surgical outcomes with respect to kinematic variables has enormous value for patients and professionals. Long-term follow-up is needed to see if the aforementioned gains improve.

Effects of resistance exercise combined with vascular occlusion on muscle function in athletes.

The effects of resistance exercise combined with vascular occlusion on muscle function were investigated in highly trained athletes. Elite rugby players (n = 17) took part in an 8 week study of exercise training of the knee extensor muscles, in which low-intensity [about 50% of one repetition maximum] exercise combined with an occlusion pressure of about 200 mmHg (LIO, n = 6), low-intensity exercise without the occlusion (LI, n = 6), and no exercise training (untrained control, n = 5) were included. The exercise in the LI group was of the same intensity and amount as in the LIO group. The LIO group showed a significantly larger increase in isokinetic knee extension torque than that in the other two groups (P < 0.05) at all the velocities studied. On the other hand, no significant difference was seen between LI and the control group. In the LIO group, the cross-sectional area of knee extensors increased significantly (P < 0.01), suggesting that the increase in knee extension strength was mainly caused by muscle hypertrophy. The dynamic endurance of knee extensors estimated from the decreases in mechanical work production and peak force after 50 repeated concentric contractions was also improved after LIO, whereas no significant change was observed in the LI and control groups. The results indicated that low-intensity resistance exercise causes, in almost fully trained athletes, increases in muscle size, strength and endurance, when combined with vascular occlusion.

Physical activity and the changes in maximal isometric strength in men and women from the age of 75 to 80 years.

To research the natural changes in maximal isometric strength, over a period of 5 years, in men and women aged 75 at baseline, and to study the effect of everyday physical activity on strength alterations. A 5-year longitudinal study. Exercise laboratory. The target group in 1989 was the total 75-year-old population of Jyväskylä. One hundred one men (81%) and 186 women (75%) participated in baseline strength tests, and after 5 years, 55 men and 111 women (70% and 72% of the survivors) took part in the follow-up measurements. Maximal isometric hand grip, arm flexion, knee extension, trunk flexion, and trunk extension forces were measured using dynamometers. Self-rated physical activity was recorded using a scale by Grimby (1986). Strength changes were compared between groups based on the amount of everyday physical activity: (1) remained active (AA, 24 men, 24 women); (2) remained sedentary (SS, 11 men, 43 women); (3) decreased activity (AS, 11 women); and (4) increased activity (SA, 32 women). AS and SA could be formed for women only because of the small number of men. All analyses were stratified by gender. The average percentage change in strength over 5 years among survivors varied from a 4% increase in knee extension strength observed in men and women to a 16% decrease in grip strength in women. The grip strength decrease was greater in women than men. The AA men maintained their trunk extension strength at a higher level than the SS men. Time by group interactions in men were not significant. In women, the rate of decline in AS was 32% in grip and 27% in elbow flexion strength, which was greater than in the other activity groups. The AA women retained their knee extension strength at a higher level than the other groups. Those who died before follow-up tests exhibited poorer strength test results at baseline. Physical activity decreased over follow-up. Strength alterations with age differed between muscle groups. Undertaking everyday physical activities such as household work, walking, and gardening, which are also the most common physically demanding activities of older people, may play an important role in maintaining strength at an adequate level for independent living.

The effect of amphetamines on selected physiological components related to athletic success

Six male college students were tested under two experimental conditions; amphetamine and no amphetamine. Each subject was tested three times under each condition. A double-blind placebo-controlled approach was employed and on six consecutive Fridays the subjects received either a placebo or 15 mg of Dexedrine per 70 kg of body weight 2 hours prior to testing. The physiological components tested were strength, muscular power, running speed, acceleration, aerobic power, and anaerobic capacity. Other variables evaluated were pre-exercise and maximum heart rates, respiratory exchange ratio and time to exhaustion. Data analysis revealed significant increases in knee extension strength, acceleration, anaerobic capacity, time to exhaustion, and pre-exercise and maximum heart rates. The most revealing results were in the area of increased time to exhaustion during the Vo2max test presumably due to higher lactic acid tolerance, thus a possible rationale to substantiate the theory that this drug has the ability to mask fatigue. It may also be possible that the biochemical actions of the drug alter fatigue processes directly. The results demonstrate that amphetamines have no effect on aerobic power, but further research will be necessary to clarify the drug's influence on muscular power-dominated movements.