**Functional Recovery and Muscle Properties After Stroke: A Preliminary Longitudinal Study**

Astrid Horstman, Arnold de Haan, Manin Konijnenbelt, Thomas Janssen and Karin Gerrits *VU University Amsterdam, The Netherlands*

## **1. Introduction**

14 Will-be-set-by-IN-TECH

66 Rehabilitation Medicine

Hanna, C. M., Fulcher, M. L., Elley, C. R. & Moyes, S. A. (2010). Normative values

Janssen, J. C. & Le-Ngoc, L. (2009). Intratester reliability and validity of concentric

Kannus, P. (1994). Isokinetic evaluation of muscular performance: implications for muscle

Li, R. C., Jasiewicz, J. M., Middleton, J., Condie, P., Barriskill, A., Hebnes, H. & Purcell, B.

Lund, H., Søndergaard, K., Zachariassen, T., Christensen, R., Bülow, P., Henriksen, M., Bartels,

lido dynamometers, *Clinical Physiology and Functional Imaging* 25(2): 75–82. Martin, H., Yule, V., Syddall, H., Dennison, E., Cooper, C. & Aihie Sayer, A. (2006).

Mital, A., Kopardekar, P. & Motorwala, A. (1995). Isokinetic pull strengths in the vertical plane: effects of speed and arm angle, *Clinical Biomechanics* 10(2): 110–112. Osternig, L. R. (1986). Isokinetic dynamometry: implications for muscle testing and rehabilitation, *Exercise and Sport Sciences Reviews* 14: 45–80. PMID: 3525192. Petty, N. (2011). *Neuromusculoskeletal examination and assessment : a handbook for therapists*, 4th

Roebroeck, M. E., Harlaar, J. & Lankhorst, G. J. (1998). Reliability assessment of isometric knee

van der Ploeg, R. J., Oosterhuis, H. J. & Reuvekamp, J. (1984). Measuring muscle strength,

Wikholm, J. B. & Bohannon, R. W. (1991). Hand-held dynamometer measurements: Tester

extension measurements with a computer-assisted hand-held dynamometer, *Archives*

(2010). Reliability of hand held dynamometric strength testing in people with diabetes/chronic conditions, *New Zealand Journal of Physiotherapy* 38 (2): 52–55. Stark, T., Walker, B., Phillips, J., Fejer, R. & Beck, R. (2011). Hand-held dynamometry

correlation with the gold standard isokinetic dynamometry: A systematic review,

strength makes a difference, *The Journal of Orthopaedic and Sports Physical Therapy*

ed. edn, Churchill Livingstone/Elsevier, Edinburgh ; New York.

*Physical Medicine and Rehabilitation* 3(5): 472–479.

13(4): 191–198. PMID: 18796845.

*Journal of Neurology* 231(4): 200–203. PMID: 6512574.

*of Physical Medicine and Rehabilitation* 79(4): 442–448. PMID: 9552112. Sole, G., Wright, L., Wassinger, C., Higgs, C., Hansson, M., Johansson, S. & Todd, N.

dynamometry, *Journal of Science and Medicine in Sport* 13(3): 299–303. Harlaar, J., Roebroeck, M. E. & Lankhorst, G. J. (1996). Computer-assisted hand-held

medicine, *Medical & Biological Engineering & Computing* 34(5): 329–335. Hyde, S. A., Goddard, C. M. & Scott, O. M. (1983). The myometer: the development of a

clinical tool, *Physiotherapy* 69(12): 424–427. PMID: 6665080.

*and Rehabilitation* 90(9): 1541–1547.

PMID: 8157377.

87(3): 411–417.

*Gerontology* 52(3): 154–159.

of hip strength in adult male association football players assessed by handheld

dynamometer: low-cost instrument for muscle function assessment in rehabilitation

measurements using a new Hand-Held dynamometer, *Archives of Physical Medicine*

testing and rehabilitation, *International Journal of Sports Medicine* 15 Suppl 1: S11–18.

(2006). The development, validity, and reliability of a manual muscle testing device with integrated limb position sensors, *Archives of Physical Medicine and Rehabilitation*

E. M., Danneskiold-Samsøe, B. & Bliddal, H. (2005). Learning effect of isokinetic measurements in healthy subjects, and reliability and comparability of biodex and

Is Hand-Held dynamometry useful for the measurement of quadriceps strength in older people? a comparison with the gold standard biodex dynamometry, Almost all patients with stroke experience a certain degree of functional recovery within the first six months after stroke. Most recovery of motor and functional performance is seen in the first month after stroke (Gray et al., 1990; Duncan et al., 1992, 1994; Jorgensen et al., 1995; Horgan & Finn, 1997; Kong et al., 2011) but improvement may continue as long as 6–12 months after stroke (Bonita & Beaglehole, 1988). Verheyden et al. (2008) observed most improvement for trunk, arm, leg and functional recovery from 1 week to 1 month after stroke and then to a lesser extent between 1 and 3 months after stroke. Only small, not statistically significant changes could be seen between 3 and 6 months after stroke, indicating that a "plateau phase" was already reached at 3 months after stroke. Further improvement after 6 months can be expected but is mostly limited (Mayo et al., 1999; Hendricks et al., 2002; Desrosiers et al., 2003; Kwakkel et al., 2004). Six months after stroke, only 60% of people with initial hemiparesis have achieved functional independence in simple activities of daily living such as toileting and walking short distances (Mayo et al., 1999; Patel et al., 2000). However, improvements in activities of daily living may continue despite stable deficits at the level of impairment. This is suggestive of further behavioral adaptation or compensation. Rehabilitation is devoted to enlarge and precipitate this functional recovery in order to improve quality of life after stroke (Gresham et al., 1995). Therefore, rehabilitation programs adapted to objectives as allowed by the state of the neuromuscular system are important.

Many daily activities, especially locomotion, require sufficient function of thigh muscles. A number of studies reported that lower extremity muscles are weaker in patients with stroke compared to healthy controls (Newham & Hsiao, 2001; Bohannon, 2007b; Sullivan et al., 2007; Horstman et al., 2008). Furthermore, the inability to generate normal amounts of force has been suggested to be the major limitation of physical activity (Mercier & Bourbonnais, 2004; Ada et al., 2006). More specific, intrinsic strength capacity as well as the ability to maximally activate the knee extensors correlate strongly with functional performance (daily activities) in patients with stroke (Bohannon, 1988, 1989; Corrigan & Bohannon, 2001; Kim & Eng, 2003; Bohannon, 2007b; Patterson et al., 2007; Horstman et al., 2008). In addition, a

Subject no.

Gender Age

(yrs)

Table 1. Subject characteristics.

**2.3 Experimental procedures** 

**2.3.1 Functional performance tests** 

**2.2 Experimental set-up** 

Weight (kg)

Height (cm)

four different days with at least one day of rest in between.

with stroke will fall (Berg et al., 1989, 1992, 1995).

1975). Maximal possible score is 34.

tests applies the higher the score, the better.

Time after stroke (days)

1 Male 65 70 172 189 29 R I F3 2 Male 61 89 172 84 67 L H F3 3 Male 61 80 182 52 76 L I F3 4 Male 52 79 172 87 55 L H F2 5 Male 55 81 177 167 145 R I F2 6 Male 56 80 168 77 41 L I F1 7 Female 26 63 170 110 52 R I F1 8 Female 62 60 168 55 61 R I F1 9 Female 61 40 150 123 76 L H t=0 10 Male 57 69 180 170 70 R I t=0 11 Female 64 74 170 117 90 L I t=0 12 Male 45 80 190 79 35 R H t=0 13 Male 67 100 190 157 114 R H t=0 14 Male 58 83 178 56 29 R I t=0

Functional Recovery and Muscle Properties After Stroke: A Preliminary Longitudinal Study 69

Body function and activity-participation level were assessed with different clinical tests ('functional performance' tests). In addition, muscle function characteristics of the kneeextensors and -flexors were assessed in both limbs. The measurements were spread over

The following tests were performed by the subjects under supervision of a physiotherapist (except for the Rivermead Mobility Index, which was carried out by one of the researchers): *Berg Balance Scale (BBS)* assesses sitting and standing balance and exists of 14 test-items, scored on an ordinal 5-point scale (0-4). It gives an estimation of the chance that patients

 *Brunnstrom Fugl-Meyer (FM), lower extremity,* is a test for evaluation of patellar, knee flexor and Achilles reflexes, flexor and extensor synergies, isolated movements of knee flexor and ankle dorsal flexor function and normal reflex activity of the quadriceps and triceps surae muscles in the paretic lower limb hemiplegic patients (Fugl-Meyer et al.,

 *Rivermead Mobility Index (RMI)* comprises a series of 14 questions and one direct observation, and covers a range of activities from turning over in bed to running. It is a measure of mobility disability which concentrates on body mobility (Collen et al., 1991). *Timed "get-up-and-*go" test (TUG) requires patients to stand up from a chair, walk 3m, turn around, return, and sit down again. Time to fulfil this test is measured (Podsiadlo & Richardson, 1991). The shorter the time needed to do this test, the better; for all other

Time after admission (days)

Side of lesion (Left/ Right)

Ischaemic/ Hemorrhage Last

measurement

recent study showed a significant association between paretic lower limb strength and balance both *cross-sectionally* in *acute* patients with stroke as well as *longitudinally* in *postacute* patients (van Nes et al., 2009).

Besides a reduction in maximal muscle strength, the ability to generate torque as fast as possible, is also impaired after stroke (Horstman et al., 2010; Bohannon & Walsh, 1992; Gerrits et al., 2009). Rate of torque development is an important determinant of e.g. risk of falling and (again) for controlling balance (Shigematsu et al., 2006; Pijnappels et al., 2008). Recent work from our group has shown lower maximal rates of torque development during electrically stimulated (Horstman et al., 2010; Gerrits et al., 2009) as well as during voluntary (Horstman et al., 2010) contractions of the paretic and non-paretic knee-extensors. Decreased ability to rapidly develop knee extension torque contributes more to lower walking speed after stroke than does maximal strength (Pohl et al., 2002).

In summary, there is clear evidence that difficulties in executing daily tasks in patients with stroke are related to both impaired strength and speed of paretic and/or non-paretic muscles. Nevertheless, most studies are performed at one point in time (Kim & Eng, 2003; Mercier & Bourbonnais, 2004; Ada et al., 2006; Bohannon, 2007b; Patterson et al., 2007; Horstman et al., 2008). It is not fully elucidated whether the improvements in functional performance at the activity level of patients with stroke during rehabilitation relate to changes in specific contractile function of the thigh muscles. Therefore, the present study reports on *longitudinal* changes in functional performance in a group of patients with stroke during the first year after stroke. Furthermore, it is determined whether these changes relate to alterations in strength and speed characteristics of the paretic and non-paretic thigh muscles and voluntary activation capacity of patients with stroke.
