Quantitative assessment of motor fatigue: Normative values and comparison with prior‐polio patients

Abstract

Motor fatigue is a common complaint of polio survivors and has a negative impact on activities of daily living. The aim of this study was to establish a normative database for hand grip strength and fatigue and to investigate differences between prior-polio subjects and normal controls. Static and dynamic hand grip fatigue and maximum voluntary isometric contraction (MVIC) of hand grip were measured in subjects with a prior history of polio (n = 44) and healthy controls (n = 494). A normative database of fatigue was developed using four indices of analysis. Compared with healthy controls, subjects with prior polio had significantly reduced hand grip strength but developed greater hand grip fatigue in only one fatigue index. Quantitative measurement of fatigue in the prior-polio population may be useful in order to detect change over time and to evaluate treatment strategies.

Assessment of subjective and motor fatigue in Polio survivors, attending a Postpolio clinic, comparison with healthy controls and an exploration of clinical correlates

“…Each test was completed if the participant had adequate power to generate a resistance against the load cell or dynamometer; otherwise, a score of zero was given. Hand grip static fatigue, of the dominant hand, was measured by maintaining maximal hand grip for 30 s and percentage fatigue was calculated using fatigue index 3 (Figure 1), described in detail previously (Meldrum et al, 2007b;Schwid et al, 1999). The same method was applied to the dominant side lower limb movements, which were strong enough to generate a resistance against the load cell, providing static fatigue measurements over 30 s for hip flexion, knee flexion and extension and ankle dorsiflexion.…”

“…The power calculation was based on published scores of mean hand grip static fatigue of 29.9% in Polio survivors and 23.7% in controls from 45 to 70 years, with a SD of 5.9% (Meldrum et al, 2007b). This calculation indicated that 26 participants in each group would be required to achieve a power of 0.95 and Type I error of 0.05.…”

“…There is some evidence that motor fatigue in Polio survivors occurs at the level of the muscle, with changes in excitation contraction coupling, with some evidence also of centrally driven fatigue (Allen, Gandevia, and Middleton, 1997;Sharma et al, 1994;Sunnerhagen et al, 2000). Significantly greater motor fatigue of hand grip in Polio survivors compared with healthy controls has been quantified using decline in maximum voluntary contraction (Meldrum et al, 2007b), but it is uncertain how motor fatigue relates to the subjective perception of fatigue, mobility, function and well-being.…”

“…Subjective fatigue, pain and weakness are well documented in Polio survivors, however motor fatigue requires evaluation, as a distinct phenomenon that may interact with these impairments (Meldrum et al, 2007b;Schwid et al, 1999). Motor fatigue and weakness may independently contribute to declining mobility, as there may be greater impairment of continuous muscle activity than of the forces of short duration typically produced to assess strength (Meldrum et al, 2007a;Nollet et al, 1999).…”

Intra‐rater Reliability of Arm and Hand Muscle Strength Measurements in Persons With Late Effects of Polio

“…The muscle weakness often affects the lower limbs, but in approximately 60% of persons with late effects of polio, muscle weakness also occurs in the upper limbs [4]. Studies have shown that persons who had polio in the past have significantly reduced grip strength [4,5] and isometric elbow muscle strength [6,7] compared with healthy persons, which has an impact on their ability to perform daily activities with their hands [4].…”