Effects of velocity on maximal torque production in poststroke hemiparesis.

نویسندگان

  • Peter S Lum
  • Carolynn Patten
  • Dhara Kothari
  • Ruth Yap
چکیده

Impaired torque production is a major physical impairment following stroke, and has been studied extensively in isometric conditions. However, functional use of a limb requires torque production during movement, and the effects of velocity on maximal torque production may be abnormally enhanced in the paretic limb. The purpose of this study was to quantify the effects of movement velocity on maximal torque production during isokinetic, concentric flexion and extension of the elbow in poststroke subjects. Three speeds were tested (30, 75, 120 deg/s) over a 100-deg range of motion. To control for strength variations between subjects and limbs, isokinetic torques were normalized by peak isometric torque. As flexion velocity increased, paretic limb torque decreased at a greater rate than in the unaffected limb. During extension, paretic limb torque was much lower than torque in the unaffected limb at all speeds. In both flexion and extension, the disparity between limbs in the constant-velocity torque-angle curves became more pronounced as velocity increased. Torque decreased 44% +/- 7% in flexion and 63% +/- 9% in extension as velocity increased from 30 to 120 deg/s, whereas the corresponding decreases in the unaffected limb were only 9% +/- 5% in flexion and 16% +/- 4% in extension. No electromyographic (EMG) abnormalities were observed during flexion. During extension, EMG data provided evidence for abnormally increased antagonist coactivation in brachioradialis and markedly reduced activation in triceps as potential contributors to the decreased extension torques. The finding that movement velocity produces large deficits in maximal torque might explain why functional use of the paretic limb is often impaired even though isometric strength appears adequate.

برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

ثبت نام

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

منابع مشابه

A Validity Study of the Modified Tardieu Scale in Measruing Poststroke Knee Extensor Spasticity

Background & Aims: The Modified Tardieu Scale (MTS) is a clinical scale for measuring the degree of muscle spasticity. The aim of this study was to evaluate the validity of the MTS in measuring poststroke knee extensorspasticity. Methods: This was a cross-sectional study performed in 2012 at a university clinic of neurological physiotherapy in Tehran, Iran, with repeated measurements. In the pr...

متن کامل

Test-retest reliability of isokinetic muscle strength of the lower extremities in patients with stroke.

OBJECTIVE To i the test-retest reliability of isokinetic strength measurements of 3 muscle groups of the lower extremities in stroke patients. DESIGN Isokineth tests of bilateral hip flexors, knee extensors, and ankle plantarflexors at 2 angular velocities, performed during 2 sessions scheduled 1 week apart for each subject. SETTING Outpatilitation clinic of a local hospital in Taiwan. PA...

متن کامل

Strength deficit of knee flexors is dependent on hip position in adults with chronic hemiparesis.

BACKGROUND The extent to which muscle length affects force production in paretic lower limb muscles after stroke in comparison to controls has not been established. OBJECTIVES To investigate knee flexor strength deficits dependent on hip joint position in adults with hemiparesis and compare with healthy controls. METHOD a cross-sectional study with ten subjects with chronic (63±40 months) h...

متن کامل

Grip type and task goal modify reach-to-grasp performance in post-stroke hemiparesis.

This study investigated whether grip type and/or task goal influenced reaching and grasping performance in poststroke hemiparesis. Sixteen adults with poststroke hemiparesis and twelve healthy adults reached to and grasped a cylindrical object using one of two grip types (3-finger or palmar) to achieve one of two task goals (hold or lift). Performance of the stroke group was characteristic of h...

متن کامل

What change in isokinetic knee muscle strength can be detected in men and women with hemiparesis after stroke?

OBJECTIVE To assess the intra-rater (between occasions) test-retest reliability of isokinetic knee muscle strength measurements in subjects with chronic poststroke hemiparesis and to define limits for the smallest change that indicates real (clinical) improvements for stroke patients. SUBJECTS Fifty men and women (mean age 58 +/- 6.4 years) 6-46 months post stroke, able to walk at least 300 m...

متن کامل

ذخیره در منابع من


  با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید

برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

ثبت نام

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

عنوان ژورنال:
  • Muscle & nerve

دوره 30 6  شماره 

صفحات  -

تاریخ انتشار 2004