Exercise and Strengthening

Exercise as a rehabilitative therapy in SCI involves the use of repetitive and effortful muscle contractions to increase motor unit activity (Sandrow-Feinberg et al. 2009; Ada et al. 2006). Exercise may be classified as strength training or functional strength training. Strength training involves isolation and stabilization of muscles through training protocols involving free weights or machines (Tomlijenovic et al. 2011), while functional strength training utilizes training programs centered around activities of daily living (Tomlijenovic et al. 2011). These exercises often involve multiple muscle groups and require functional movements that are more applicable to daily life, thereby improving strength for performing everyday tasks (Tomlijenovic et al. 2011).

Engaging in repetitive physical therapy that is active or passive has many beneficial effects for individuals with SCI including preserved muscle mass (Houle et al. 1999), restored motor and sensory function (Hutchinson et al. 2004. Sandrow-Feinberg et al. 2009), induced synaptic plasticity by way of neurotrophic factor production (Vaynman et al. 2003), increased concentration of neurotrophic factors in spinal and muscle tissue (Gomez-Pinilla et al. 2002; Ying et al. 2005; Cote et al. 2011) and reduced inflammation around the lesion site (Sandrow-Feinberg et al. 2009). However, SCI often limits an individual’s ability to partake in exercise (Crane et al. 2015). This is a contributing factor to the incidence of obesity, cardiovascular disease and diabetes is two to four times higher in individuals with SCI compared to the general population (Evans et al. 2015).

Few evidence-based analyses on the efficacy of specific exercise therapies on upper extremity function exist (Ginis et al. 2008). The majority of research has focused on individual components of physical capacity (e.g. peak oxygen uptake, muscle strength, or respiratory function), rather than functional outcomes. Additional studies regarding cardiovascular and exercise interventions are discussed in the Cardiovascular chapter and Physical Activity chapter.

The methodological details and results from seven studies evaluating exercise and strengthening for upper extremity function are presented in Table 1.

Author Year

Country

Research Design

Score

Total Sample Size

Methods Outcome
Trumbower et al., 2017

USA

RCT – Crossover

PEDro=9

N=6

Population: Mean age=43±5 yr; Gender: males=6; Time since injury: 19±1 yr; Level of injury: C5; Severity of injury: AISA C=3, D=3.

Intervention: Participants were randomized to normal or hypoxic conditions. Participants received daily (five consecutive d) acute intermittent hypoxia (AIH), which consisted of 15 episodes per day: 1.5 min of fraction inspired oxygen [FIO2] = 0.09, 1-min normoxic intervals) followed by 20 repetitions of hand opening practice and normoxia (sham FIo2=0.21). Treatments were followed by a two wk minimum wash out period. Outcome measures were assessed at baseline and one wk for each treatment group.

Outcome Measures: Hand dexterity and function – Box and Block hand function test; Jebsen-Taylor hand function test (JTHF); Maximum hand opening.

1.     Daily AIH and hand opening practice improved hand dexterity, function and maximum hand opening in all participants but was not statistically significant (p>0.05).

2.     AIH and hand opening practice significantly improved Box and Block Test scores versus controls in all 6 participants (p=0.016).

3.     No statistically significant difference was observed in JTHF between groups (p>0.05), however, all participants reduced their JTHF score after daily AIH and hand opening practice versus controls.

4.     Maximum hand opening versus baseline significantly improved with AIH and hand opening practice when compared to controls (p=0.030).

Nightingale et al., 2018

U.K.

RCT

PEDro=7

N=21

Population: Mean age=47±8 yr; Gender: males=15, females=6; Time since injury: 16±11 yr; Level of injury: T4 and below; Severity of injury: not reported.

Intervention: Participants were randomly assigned to a home-based moderate-intensity upper-body exercise intervention (n=13) or a lifestyle maintenance control group (n=8) for 6 weeks. Outcome measures were assessed at baseline and follow-up.

Outcome Measures: Physical and mental component scores (PCS and MCS); Health related quality of life (HRQOL); Fatigue; Global fatigue (FSS); WUPSI.

1.     The exercise intervention group significantly improved PCS and MCS (p=0.017) and FSS (p=0.036) outcomes in relation to controls.

2.     No statistically significant difference was observed in fatigue and WUPSI between groups(p>0.05).

Hicks et al., 2003

Canada

RCT

PEDro=5

NInitial=34; NFinal=11

Population: Age: 19-65 yr; Level of injury: C4-L1; Severity of injury: AIS A-D; Time since injury: 1-24 yr.

Intervention: Experimental group (EX) participated in progressive exercise training twice weekly for nine mo-each session offered on alternative days lasing 90-120 min.

Outcome Measures: Perceived stress scale, Muscle strength, Depression, Physical self-concept pain, Perceived health, Quality of Life (QoL).

1.     Overall 11 in the EX group (exercise adherence 82.5%) and 13 in the control group completed the study.

2.     No differences were noted between the two groups at baseline.

3.     Following training, EX group had significant increases in sub maximal arm ergometry power output (81%; p<0.05) and significant increases in upper body muscle strength (19-34%; p<0.05).

4.     EX group reported less pain, stress and depression after training + scored higher than CON in indices of satisfaction with physical function, level of perceived health + overall quality of life (p<0.05).

Haisma et al., 2006

Netherlands

Prospective Cohort

NInitial=186; NFinal=42

Population: Mean age: 40 yr; Gender: males=140, females=46; Level of Injury: paraplegia, tetraplegia; Severity of injury: complete=125, incomplete=61; Mean time since injury: 105 d.

Intervention: Assessments were taken at four time points: start of inpatient rehabilitation; three months later; discharge and at one year after discharge.

Outcome Measures: Power output (PO) peak, VO2 peak, strength of upper extremity, respiratory function.

1.     Age was related to the PO peak and handheld dynamometry (HHD) score (p<0.05), the older the subject the more improvement in either of these measures was significantly less than it was in younger subjects.

2.     Men had greater PO peak, VOpeak and HHD score than women did (p<0.05), thus improvement in men was greater than women.

3.     In tetraplegia subjects the PO peak, VOpeak, muscle strength and % of forced vital capacity (FVC) was lower (p<0.05) than it was in paraplegia subjects, but tetraplegia subjects improved more in muscle strength and % of forced expiratory flow (FEV1).

4.     Those with a complete lesion had greater HHD score and lower % of FVC than those with incomplete lesions (p<0.05).

Gant et al., 2018

USA

Pre-Post

N=8

Population: Mean age=31.4 yr; Gender: males=6, females=2; Time since injury: 10.5 yr; Level of injury: T2 – T10; Severity of injury: AISA A=4, B=4.

Intervention: Participants underwent three, four wk long multi-modal exercise conditioning and rehabilitation interventions, each separated by a one wk period of multiple body systems assessments.

Each participant was in the trial for 19 contiguous weeks. Outcome measurements were assessed after screening for two baseline assessments and at four, nine, 14 and 19 wk.

Outcome Measures: Neurological motor and sensory impairment; Upper extremity muscle strength and peak oxygen consumption; Blood pressure; Cholesterol, lipids and biomarkers or glycemic control and inflammation; Clinical and electrophysiological spasticity measures; Pain history and pain-related sensory function; Self-reported function; Patient global impression of change.

1.     No significant differences in neurological motor and sensory impairment, blood pressure, cholesterol, lipids, biomarkers of glycemic control and inflammation, as well as chronic pain were observed (p>0.05).

2.     Upper extremity muscle strength significantly improved from baseline (p=0.001); Peak oxygen consumption was not significantly different from baseline (p>0.05).

3.     Participants with high soleus (SL) and tibialis anterior (TA) F/M spasticity ratios at baseline improved significantly (p=0.001); Participants with high SL F/M spasticity ratios at baseline had a significant decrease in the Spinal Cord Assessment Tool for Spastic reflexes (SCATS) extensor score (p=0.047); Other measures of spasticity were not significant (p>0.05).

4.     Two participants experienced clinically significant improvements in self-reported function (p<0.05).

5.     All participants reported a perceived improvement.

Hoffman et al., 2017

USA

Pre-Post

N=17

Population: Mean age=31.3 yr; Gender: males=10, females=7; Time since injury: 7.6 yr; Level of injury: C1 – C7; Severity of injury: AISA A=12, B=1, C=2, D=2.

Intervention: Patients with SCI were enrolled in a weekly hand-focused therapy program that involved using a novel handgrip device on grip strength and hand function. Outcome measures were assessed at baseline and once a wk until the end of the trial at 20 wk.

Outcome Measures: Maximum voluntary contraction (MVC); Mean absolute accuracy (MAA); SCIM.

1.     The average MVC increased from 4.1N to 21.2N over 20 wk, but did not reach statistical significance (p>0.05).

2.     The average MAA significantly increased from 9 to 21% at the end of the study (p=0.02).

3.     The average SCIM was unchanged from baseline to the end of the study (p>0.05).

Drolet et al., 1999

Canada

Pre-post

NInitial=40; NFinal=31

Population: Mean age: 29.5 yr; Gender: males=27, females=4; Level of injury: paraplegia=18, tetraplegia=13; Severity of injury: AIS A-D; Mean time since injury: 2 mo; Mean length of stay: 4.5 mo.

Intervention: Rehab included physiotherapy (PT), occupational therapy (OT) and physical conditioning. There were four 1 hr sessions of each intervention.

Outcome Measures: Mean muscle strength, Muscle strength changes.

1.     Strength values at admittance were inversely repeated to strengthen changes during rehab (Pearson correlation coefficients ranging from -0.47 (p=0.001 shoulder flexors) to -0.73 (p<0.001 shoulder adductors).

2.     For those with paraplegia the range was from -0.48 (p=0.049 shoulder abductors to -0.72 (p=0.001 elbow flexors) compared to those with tetraplegia, the correlation coefficients ranged from -0.28 (p=0.345 elbow extensors) to -0.68 (p=0.010 shoulder adductors).

3.     Patterns of change in muscle strength from admittance to the 15 mo follow up differed between the paraplegia group and the tetraplegia group.

4.     Differences in strength have been observed for: elbow flexors (p=0.001) and shoulder extensors (p=0.04).

Discussion

All seven studies presented found that exercise and strengthening were effective in improving upper extremity function. To date, these are the only studies that have tested exercise and strengthening for upper extremity rehabilitation in SCI. Interestingly, across all studies a wide variety of different types of exercise were efficacious. Trumbower and colleagues (2017) found that acute intermittent hypoxia, when combined with hand opening exercise improved hand function in individuals with SCI. Nightingale et al. (2018) investigated the efficacy of a home-based exercise program and found it improved health-related quality of life. Hicks et al. (2003), Haisma et al. (2006), and Drolet et al. (1999) studied traditional in-patient exercise rehabilitation programs and found significant improvements in upper extremity function. Study participants also reported decreases in stress, pain, depression, enhanced physical self-concept, and overall quality of life. Similarly, Hoffman et al. (2017) demonstrated significant improvements in hand function with the completion of a more traditional activity-based rehabilitation therapy. Gant et al. (2018) found significant improvements in upper extremity muscle strength with a multi-modal exercise training program. In this training program, a combination of activities was performed including body-weight-treadmill training, circuit resistance training for upper body conditioning, functional electrical stimulation, and wheelchair skills training.

In summary, regardless of the training modality used, individuals experienced increases in muscle strength, hand function, and quality of life. However, further research is necessary to directly compare the efficacy of each exercise/strength training program to each other. In addition, Haisma et al. (2006) and Sipski and Richards (2006) recommended further research in a variety of areas including optimal methods for strengthening muscles, merits of endurance versus strength training, and ROM, ADL, and transfer training. the impact of body composition, age, and concomitant medical problems on exercise efficacy should also be explored. Furthermore, longitudinal studies are needed to gain more insight into the changes that occur after inpatient rehabilitation and the factors which influence these changes.

Conclusion

There is level 1b evidence (from one randomized controlled trial: Trumbower et al. 2017) that acute intermittent hypoxia combined with daily hand opening practice significantly improves hand opening in some, but not all, aspects of hand function.

There is level 1b evidence (from one randomized controlled trial: Nightingale et al. 2018) that six weeks of home-based upper-body exercise improves aspects of health-related quality of life.

There is level 2 evidence (from one randomized controlled trial: Hicks et al. 2003) that physical capacity continues to improve 1- year post-discharge and is correlated to a decrease in stress, pain, and depression.

There is level 2 evidence (from one prospective controlled trial: Haisma et al. 2006) that physical capacity (strength and respiratory function) improves during and after inpatient rehabilitation.

There is level 4 evidence (from one pre-post study: Gant et al. 2018) that multi-modal exercise improves muscle strength and function in individuals with SCI.

There is level 4 evidence (from one pre-post study: Hoffman et al. 2017) that weekly activity-based hand therapy is feasible and efficacious at increasing hand task performance in individuals with SCI.

There is level 4 evidence (from one pre-post study: Drolet et al. 1999) that overall muscle strength continues to improve up to 15 months post-hospital discharge for both persons with tetraplegia and paraplegia despite large variability in patients.