Velocity dependence of eccentric strength in young and old men: the need for speed!

Older adults better maintain eccentric strength relative to isometric strength, as indicated by a higher ratio of eccentric:isometric torque as compared with younger adults. The effect of increasing angular velocities (>200°/s) on the age-related maintenance of eccentric strength has not been tested and thus it is unknown whether the eccentric:isometric ratio is velocity dependent in old age. The purpose of this study was to investigate eccentric strength of the ankle dorsiflexors over a large range of lengthening angular velocities in young and older men.

Golf-related low back pain: a review of causative factors and prevention strategies.

Golf is a popular sport with both perceived and real health benefits. However, certain injury risks are also prevalent, particularly to the lower back. Epidemiological studies have shown that lower back pain (LBP) from golf account for between 18% and 54% of all documented ailments, leading many researchers to regard the condition as the most common golf injury.

Shortening-induced torque depression in old men: implications for age-related power loss.

Following active muscle shortening, the steady-state isometric torque at the final muscle length is lower than the steady-state torque obtained for a purely isometric contraction at that same final muscle length. This well-documented property of skeletal muscle is termed shortening-induced torque depression (TD). Despite many investigations into the mechanisms of weakness and power loss in old age, the influence of muscle shortening on the history dependence of isometric torque production remains to be elucidated.

The effect of knee joint angle on plantar flexor power in young and old men.

Human adult aging is associated with a loss of strength, contractile velocity and hence, power. The principal plantar flexors, consisting of the bi-articular gastrocnemeii and the mono-articular soleus, appear to be affected differently by the aging process. However, the age-related effect of knee joint angle on the torque-angular velocity relationship and power production of this functionally important muscle group is unknown.

Enhanced force production in old age is not a far stretch: an investigation of residual force enhancement and muscle architecture.

In older adults, isometric force production is enhanced following a voluntary lengthening contraction when compared with isometric force produced at the same muscle length without a prior lengthening contraction. This phenomenon is termed residual force enhancement (RFE), and appears to be related to the age-related maintenance of eccentric (ECC) strength. However, it is unknown whether age-related changes in muscle architecture contribute to greater RFE at short and long muscle lengths in old age.

Peak power is reduced following lengthening contractions despite a maintenance of shortening velocity.

Following repetitive lengthening contractions, power (the product of torque and velocity) is impaired during shortening contractions. However, the relative contribution of each component to power loss and the underlying factors are unclear. We investigated neuromuscular properties of the dorsiflexors in 8 males (27 ± 3 years) and 8 females (26 ± 4 years) for a potential sex-related difference before, during, and after 150 unaccustomed maximal lengthening actions.

A literature synthesis indicates very low quality, but consistent evidence of improvements in function after surgical interventions for primary osteoarthritis of the elbow.

Background. Primary osteoarthritis of the elbow is a debilitating disease with an overall incidence of about 2%. Pain and reduced motion (ROM) lead to disability and loss of functional independence.

The genu effect on plantar flexor power.

Triceps surae function can be modified by changes in knee joint angle through altering the effective contribution of the bi-articular gastrocnemeii. However, the impact on plantar flexor power from altering knee angle has not been studied systematically across a range of loads. Here, in 11 young men (25.

Increased residual force enhancement in older adults is associated with a maintenance of eccentric strength.

Despite an age-related loss of voluntary isometric and concentric strength, muscle strength is well maintained during lengthening muscle actions (i.e., eccentric strength) in old age.

Resistance training and older adults with type 2 diabetes mellitus: strength of the evidence.

Objective. This paper analyzes the effects of resistance training (RT) on metabolic, neuromuscular, and cardiovascular functions in older adults (mean age ≥ 65 years) with type 2 diabetes (T2DM). Research Design and Methods.

Residual force enhancement following eccentric induced muscle damage.

During lengthening of an activated skeletal muscle, the force maintained following the stretch is greater than the isometric force at the same muscle length. This is termed residual force enhancement (RFE), but it is unknown how muscle damage following repeated eccentric contractions affects RFE. Using the dorsiflexors, we hypothesised muscle damage will impair the force generating sarcomeric structures leading to a reduction in RFE.

Motor unit survival in lifelong runners is muscle dependent.

Unlabelled: A contributing factor to the loss of muscle mass and strength with adult aging is the reduction in the number of functioning motor units (MUs). Recently, we reported that lifelong competitive runners (master runners = ~66 yr) had greater numbers of MUs in a leg muscle (tibialis anterior) than age-matched recreationally active controls. This suggested that long-term exposure to high levels of physical activity may limit the loss of MU numbers with adult aging.

A comparison of physical activity (PA) assessment tools across levels of frailty.

Purpose: Determine which PA assessment tools are most closely related to frailty and whether PA is different across levels of frailty.

Methods: Fifty community-dwelling Greek older women (63-90 years) participated in this study. PA was measured objectively over 10h using an accelerometer, a heart rate (HR) monitor, a portable electromyography (EMG) unit, and a global positioning system (GPS) and subjectively using the short version of the Minnesota Leisure Time Activity Questionnaire (MLTAQ).

A comparison of the relationship of 14 performance-based measures with frailty in older women.

The purpose of this study was to determine which performance measures of physical function are most closely related to frailty and whether physical function is different across levels of frailty. Fifty-three community-dwelling Greek women (63-100 years) participated in this study. Participants were divided into 3 tertiles based on level of frailty as calculated from a frailty index (FI): lowest FI group (<0.

The age-related slowing of voluntary shortening velocity exacerbates power loss during repeated fast knee extensions.

Older adults are less fatigable than young during isometric tasks, but this apparent ability to resist fatigue is often abolished when dynamic actions are performed. These findings could indicate that the velocity component of dynamic contractions or the task performed is an important factor in explaining fatigability of older adults. However, it has not been evaluated systematically.

Reproducibility of velocity-dependent power: before and after lengthening contractions.

The determination of power using isokinetic testing has been shown to be highly reliable. However, isotonic and isokinetic testing involve specific mechanical constraints that likely necessitate different neuromuscular strategies. Therefore, the purpose here was to establish test-retest intrarater reliability (separated by 7 days) of loaded maximal shortening velocity and velocity-dependent power of the ankle dorsiflexors using the isotonic mode of the Biodex dynamometer (i) at baseline and (ii) throughout recovery following 150 high-intensity lengthening contractions.

The effectiveness of exercise interventions for the management of frailty: a systematic review.

This systematic review examines the effectiveness of current exercise interventions for the management of frailty. Eight electronic databases were searched for randomized controlled trials that identified their participants as "frail" either in the title, abstract, and/or text and included exercise as an independent component of the intervention. Three of the 47 included studies utilized a validated definition of frailty to categorize participants.

Power loss is greater following lengthening contractions in old versus young women.

Compared with isometric and dynamic velocity-constrained (isokinetic) tasks, less is known regarding velocity-dependent (isotonic) muscle power and recovery in older adults following repeated fatiguing lengthening contractions. We investigated voluntary and evoked neuromuscular properties of the dorsiflexors in nine old (68.3 ± 6.

Power loss is greater in old men than young men during fast plantar flexion contractions.

It is unclear during human aging whether healthy older adults (>70 yr old) experience greater, lesser, or the same fatigability compared with younger adults. The reported disparate findings may be related to the task-dependent nature of fatigue and the limited number of studies exploring nonisometric contractile function and aging. The purpose here was to determine the effects of fast shortening contractions on the fatigability of the triceps surae in 10 young (~24 yr old) and 10 old (~78 yr old) men using isometric and dynamic measures.

Daily muscle activity and quiescence in non-frail, pre-frail, and frail older women.

Reduced muscle mass and strength are likely fundamental components of frailty. The purpose of this study was to measure daily muscle activity and quiescence in non-frail, pre-frail, and frail older women using portable electromyography (EMG). Thirty-three community-dwelling older Greek women were categorized as non-frail (n=10, 74±4years), pre-frail (n=11, 75±4years), and frail (n=12, 81±6years) based upon the frailty phenotype.

Delayed recovery of velocity-dependent power loss following eccentric actions of the ankle dorsiflexors.

Unaccustomed eccentric exercise has been shown to impair muscle function, although little is known regarding this impairment on muscle power. The purpose of this study was to investigate changes in neuromuscular properties of the ankle dorsiflexors during and after an eccentric contraction task and throughout recovery in 21 (10 men, 11 women) recreationally active young adults (25.8+/-2.

Motor unit number estimates in masters runners: use it or lose it?

Introduction: A contributing factor to the loss of muscle mass and strength during aging is the reduction in the number of functioning motor units (MU). It has been shown that lifelong physically active older rats have greater numbers of MU compared with age-matched sedentary controls, suggesting that chronic exercise may preserve MU function with advancing age. This has not previously been examined in humans.

Effect of tibial re-alignment surgery on single leg standing balance in patients with knee osteoarthritis.

Background: Standing balance is impaired in individuals with knee osteoarthritis and is associated with disease severity. The effects of surgical interventions on standing balance have received little attention. The purpose of the present study was to examine measures of balance during tests of single-limb standing before and after medial opening wedge high tibial osteotomy--a lower limb re-alignment procedure for those with varus alignment and knee osteoarthritis.

Potential benefits of warm-up for neuromuscular performance of older athletes.

Demographic trends project increasing numbers of older people to engage in exercise programs and sports. Sustained participation depends on both perceived health outcomes and avoidance of debilitating injuries. This review explores the potential benefits of physiologically based warm-up strategies to alleviate some key age-related decreases in the biomechanical capacity for skilled sport movements.