Functional implications of impaired control of submaximal hip flexion following stroke

Hyngstrom, Allison S.; Kuhnen, Henry R.; Kirking, Kiersten M.; Hunter, Sandra K.

doi:10.1002/mus.23886

Cited by 18 publications

(17 citation statements)

References 59 publications

(98 reference statements)

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“…23 Coordinated multi-joint movements that make up everyday tasks like walking are dependent on repetitive submaximal contractions and are less associated with the explosive one time movements represented by a 1-RM strength test. 22 Importantly, the magnitude of SME gains produced by our ST treatment group (150 + %) was unexpected and suggestive of newly acquired potential for altering sustainment of everyday activities. None of the other outcome measures showed comparable effect sizes.…”

Section: Discussionmentioning

confidence: 82%

Strength Training for Skeletal Muscle Endurance after Stroke

Ivey

Prior

Hafer‐Macko

et al. 2017

Journal of Stroke and Cerebrovascular Diseases

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Background and Purpose Initial studies support the use of strength training (ST) as a safe and effective intervention after stroke. Our previous work shows that relatively aggressive, higher intensity ST translates into large effect sizes for paretic and non-paretic leg muscle volume, myostatin expression, and maximum strength post-stroke. An unanswered question pertains to how our unique ST model for stroke impacts skeletal muscle endurance (SME). Thus, we now report on ST-induced adaptation in the ability to sustain isotonic muscle contraction. Methods Following screening and baseline testing, hemiparetic stroke participants were randomized to either ST or an attention-matched stretch control group (SC). Those in the ST group trained each leg individually to muscle failure (20 repetition sets, 3× per week for 3 months) on each of three pneumatic resistance machines (leg press, leg extension, and leg curl). Our primary outcome measure was SME, quantified as the number of submaximal weight leg press repetitions possible at a specified cadence. The secondary measures included one-repetition maximum strength, 6-minute walk distance (6MWD), 10-meter walk speeds, and peak aerobic capacity (VO2 peak). Results ST participants (N = 14) had significantly greater SME gains compared with SC participants (N = 16) in both the paretic (178% versus 12%, P < .01) and non-paretic legs (161% versus 12%, P < .01). These gains were accompanied by group differences for 6MWD (P < .05) and VO2 peak (P < .05). Conclusion Our ST regimen had a large impact on the capacity to sustain submaximal muscle contraction, a metric that may carry more practical significance for stroke than the often reported measures of maximum strength.

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Section: Discussionmentioning

confidence: 82%

Strength Training for Skeletal Muscle Endurance after Stroke

Ivey

Prior

Hafer‐Macko

et al. 2017

Journal of Stroke and Cerebrovascular Diseases

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“…Ten chronic (>6 months) unilateral stroke survivors (6 men and 4 women; age 54 ± 6 years, Lower Extremity Fugl‐Meyer score mean ± SD = 25 ± 4) performed the Ten‐Meter Walk Test to quantify self‐selected walking speed. Participants were positioned on a therapy table with both legs secured in a customized robotic apparatus (2 servomotor systems [Kollmorgen, Northampton, Massachusetts]) instrumented with 2 torque transducers (S. Himmelstein Company, Hoffman Estates, Illinois) . For details on the set‐up, please see previous studies .…”

Section: Methodsmentioning

confidence: 99%

“…Participants were positioned on a therapy table with both legs secured in a customized robotic apparatus (2 servomotor systems [Kollmorgen, Northampton, Massachusetts]) instrumented with 2 torque transducers (S. Himmelstein Company, Hoffman Estates, Illinois). 4,12 For details on the set-up, please see previous studies. 4,[13][14][15][16] Bipolar surface EMG was recorded from the rectus femoris (RF) and the medial hamstring (MH) muscles.…”

Section: Methodsmentioning

confidence: 99%

Stroke‐related effects on maximal dynamic hip flexor fatigability and functional implications

et al. 2015

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Introduction Stroke-related changes in maximal dynamic hip flexor muscle fatigability may be more relevant functionally than isometric hip flexor fatigability. Methods Ten subjects with chronic stroke performed 5 sets of 30 hip flexion maximal dynamic voluntary contractions (MDVC). A maximal isometric voluntary contraction (MIVC) was performed before and after completion of the dynamic contractions. Both the paretic and non-paretic legs were tested. Results Reduction in hip flexion MDVC torque in the paretic leg (44.7%) was larger than the non-paretic leg (31.7%). The paretic leg had a larger reduction in rectus femoris EMG (28.9%) between the first and last set of MDVCs than the non-paretic leg (7.4%). Reduction in paretic leg MDVC torque was correlated with self-selected walking speed (r2=0.43), while reductions in MIVC torque were not (r2=0.11). Discussion Reductions in maximal dynamic torque of paretic hip flexors may be a better predictor of walking function than for maximal isometric contractions.

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“…With respect to patient populations, patients with stroke have increased excitability of Ia pathways [ 3 , 4 ] and impairments in low-level force regulation [ 41 – 43 ] during isometric contractions. Although the mechanisms of impaired force regulation post stroke have not been fully explained, there is indirect evidence of altered coordination of agonist-antagonist activity and increased involvement of spinal pathways with and without visual feedback.…”

Section: Discussionmentioning

confidence: 99%

“…Although force regulation can be task and muscle specific, larger muscle groups of the leg tend to have worse force regulation at lower relative force levels (< ~20% of maximal voluntary contractions) as compared to higher force levels [ 8 , 9 ]. This manifests as decreased steadiness or increased error at lower force levels, and correlates with clinical measures of function [ 7 ]. The load-dependent effect on sub-maximal force regulation can be attributed to motoneuron:muscle fiber innervation ratios (lower resolution of control) [ 8 ] and, in some cases, poor temporal regulation of agonist:antagonist pairs [ 9 – 11 ].…”

Section: Introductionmentioning

confidence: 99%

The Effect of Antagonist Muscle Sensory Input on Force Regulation

2015

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The purpose of this study was to understand how stretch-related sensory feedback from an antagonist muscle affects agonist muscle output at different contraction levels in healthy adults. Ten young (25.3 ± 2.4 years), healthy subjects performed constant isometric knee flexion contractions (agonist) at 6 torque levels: 5%, 10%, 15%, 20%, 30%, and 40% of their maximal voluntary contraction. For half of the trials, subjects received patellar tendon taps (antagonist sensory feedback) during the contraction. We compared error in targeted knee flexion torque and hamstring muscle activity, with and without patellar tendon tapping, across the 6 torque levels. At lower torque levels (5%, 10%, and 15%), subjects produced greater knee torque error following tendon tapping compared with the same torque levels without tendon tapping. In contrast, we did not find any difference in torque output at higher target levels (20%, 30%, and 40%) between trials with and without tendon tapping. We also observed a load-dependent increase in the magnitude of agonist muscle activity after tendon taps, with no associated load-dependent increase in agonist and antagonist co-activation, or reflex inhibition from the antagonist tapping. The findings suggest that at relatively low muscle activity there is a deficiency in the ability to correct motor output after sensory disturbances, and cortical centers (versus sub-cortical) are likely involved.

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Functional implications of impaired control of submaximal hip flexion following stroke

Cited by 18 publications

References 59 publications

Strength Training for Skeletal Muscle Endurance after Stroke

Strength Training for Skeletal Muscle Endurance after Stroke

Stroke‐related effects on maximal dynamic hip flexor fatigability and functional implications

The Effect of Antagonist Muscle Sensory Input on Force Regulation

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