The effects of proprioceptive neuromuscular facilitation (PNF) on joint range of motion (ROM) for older adults are unknown, and few studies have investigated changes in joint ROM associated with age. This study examined PNF stretch techniques’ effects on knee-joint ROM in trained (T) and untrained (UT) older adults. Knee-joint ROM was tested in T and UT adults age 45–55 and 65–75 years using 3 PNF stretch techniques: static stretch (SS), contract relax (CR), and agonist contract-relax (ACR). The 45–55 UT group achieved significantly more ROM than did the 65–75 UT group, suggesting an agerelated decline in ROM. The 65–75 T group achieved significantly greater knee-extension ROM than did their UT counterparts, indicating a training related response to PNF stretch techniques and that lifetime training might counteract age-related declines in joint ROM. The ACR-PNF stretch condition produced 4–6° more ROM than did CR and SS for all groups except the 65–75 UT group, possibly as a result of lack of neuromuscular control or muscle strength.

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Abstract
The effects of proprioceptive neuromuscular facilitation (PNF) stretch techniques on older adults are unknown and the physiological changes associated with aging may lead to differential responses to PNF stretching. Therefore, the purpose of this experiment was to examine the effects of PNF stretch techniques and EMG activity in older adults. Three PNF stretch techniques: static stretch (SS), contract–relax (CR), and agonist contract–relax (ACR) were applied to 24 older adults aged 50–75 years. The subjects were tested for knee extension range of motion (ROM) and knee flexor muscle EMG activity. The results indicated that ACR produced 29–34% more ROM and 65–119% more EMG activity than CR and SS, respectively. It was concluded that PNF stretch techniques can increase ROM in older adults. However, a paradoxical effect was observed in that PNF stretching may not induce muscular relaxation even though ROM about a joint increases. Care should be taken when applying PNF stretch techniques to older adults due to age-related alterations in muscle elasticity.

Abstract
The purpose of this study was to compare joint couplingpatterns and variability of the rearfoot and tibia during running subjects who were treated with two types of orthotic devices to that of controls.  Eleven subjects with various lower extremity injuries were treated unsuccessfully with a standard orthotic, and then successfully with an inverted orthotic. Three-dimensional kinematic data were collected while subjects ran without orthoses and then in standard and inverted orthoses.  Eleven healthy subjects ran without orthoses for comparison.  The rearfoot inversion/eversion and tibial internal/external rotation joint coupling pattern and variability relationship was assessed using a vector coding technique. It was hypothesized that when the treated runners ran without orthotic devices, they would exhibit lower joint coupling ang les and lower joint coupling variability compared to the controls.  In addition, it was hypothesized that there would be no difference in the coupling angle or coupling variability between the standard and no orthotic conditions of the treated runners.  Finally, it was hypothesized that couplingang angle would decrease and variability would increase in the inverted versus the standard and non-orthotic conditions.  No significant differences in joint coupling patternor variability were observed between the treated and control subjects. In addition, no significant differences were noted between theorthotic conditions in the treated group. These results suggest that foot orthotic devices do not produce significant changes inrearfoot–tibial coupling. Therefore, the relief experienced with the inverted orthotic is likely due to factors other than alterations in this coupling.

The importance of core stability to prevent and treat running injuries ore stability training is gaining popularity in the running community as more runners are madeaware of how weakness in the “core” of the body can negatively influence lower extremity iomechanics and running performance.  The lumbar, pelvis and hip region together areconsidered to be the core of the body and optimal core function involves both mobility and tability.  When the core is functioning efficiently, advantageous length-tension relationships aremaintained which allow the runner to produce strong movements in the extremities. More mportantly, proper core stability can help maximize running performance, maintain the center ofgravity over the base of support, control lower extremity limb motion while running, and help revent running-related injuries.

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Abstract

Objective:

To determine bilateral lower extremity joint accommodations during gait in anterior cruciate ligament deficient subjects and uninjured controls.Design. Gait testing of 10 chronic anterior cruciate ligament deficient subjects prior to and 3 months following reconstructive surgery, and 10 uninjured controls.

Background:

It is possible that bilateral joint accommodations could occur as a result of anterior cruciate ligament injury and in response to surgical repair.  Few studies have investigated bilateral joint accommodations to anterior cruciate ligament injury andthere is little consistency in the reported results.

Methods:

Bilateral lower extremity kinematic and kinetic data were collected from 12 walking trials and inverse dynamics calculationswere made to estimate bilateral knee and hip joint angle, moment, and power patterns during the stance phase of gait.

Results:

Control subjects exhibited asymmetrical hip but symmetrical knee joint moment and power patterns.  In contrast, theanterior cruciate ligament deficient subjects exhibited symmetrical hip and asymmetrical knee joint moment and power patternsprior to and following reconstructive surgery.

Conclusions:

Gait asymmetry in healthy subjects should not be considered pathological.  In addition, chronic anterior cruciateligament injury results in joint specific, bilateral lower extremity accommodations in gait mechanics.  These accommodations persist3 months following surgical repair.