Baldi et al. 1998; USA
PEDro = 5
RCT
N=26

Population: 26 males and females; age 25-28 yrs; traumatic motor complete; cervical or thoracic lesion level; 15 wks post-injury
Treatment: Random assignment to 3-6 months of 1. FES-assisted cycle ergometry (n=8), 30 min, 3X/week; 2. PES-assisted isometric exercise group (n=8) (same muscle groups as FES group) for 1 hr, 5X/week and 3. control group (n=9) with no stimulation.
Outcome Measures: lean body mass lower limb.

• Lean body mass increased with FES-cycling at all regions and declined for control and PES group.
• With respect to total body lean mass, lower limb lean mass and gluteal lean mass, controls lost an average of 6.1%, 10.1%, 12.4% after 3 months and 9.5%, 21.4%, 26.8% after 6 months.

Shields & Dudley-Javoroski 2006; USA
Downs & Black = 13
Prospective Controlled Trial
N=7

Population: 7 males; age 21-43 yrs; AIS A; C5-T10 lesion level; ³ 6 weeks post-injury
Treatment: PES exercise to unilateral ankle plantarflexion (untrained leg served as a control). Four 4 min exercise bouts, 5 days/week for 1.87-3.05 years.
Outcome Measures: Stimulated ankle torque and soleus twitch profiles at baseline and every 6 months up to 3 years.

Compared to the untrained side, stimulated limb had:

• ↑ strength (↑ peak stimulated ankle torque and higher torque-time integrals (p<0.05).
• More resistant to fatigue (↑muscle fatigue indexes), (p<0.05).
• Increased twitch difference (indicative of force generating capacity) (p<0.05), especially with successive stimulation trains.

Sabatier et al. 2006; USA
Downs & Black = 15
Pre-post
N=5

Population: 5 males; age 35.6±4.9 yrs; complete; C5-T10 lesion level; 13.4±6.5 yrs post-injury
Treatment: 18 weeks of neuromuscular electrical stimulation resistance training for the quadriceps combined with additional weight around the shin, 2x/week with 4 sets of knee extensions.
Outcome Measures: Weight lifted, muscle mass, muscle fatigue 

• All subjects increased weight lifted during training by an average of 6.9±1.4 kg
• Significant increases in cross-sectional area of quadriceps femoris in both thighs (right mean CSA ­ from 32.6 to 44.0 cm2, left mean ­ from 34.6 to 47.9 cm2)
• Progressive decrease in fatigue throughout training and after 18 weeks of training. Decreases significant at 12 weeks and 18 weeks.

Hjeltnes & Lannem 1990; Norway
Downs & Black = 11
Pre-post
N=4

Population: 4 males and females; age 20-36 yrs; Frankel A; T5-T12 lesion level; 3 mos-5 yrs post-injury
Treatment: PES, 4 weeks, 2x/day, 5-10mins, isokinetic resistance to quadriceps muscles followed by 4 weeks, 30 min, 2X/day, 4-5X/day of integrated training of rising and standing.
Outcome Measures: Knee extension torque, thigh circumference, creatine kinase (CK) collected monthly.

No group statistics done. At least 2 subjects had ↑ knee extension torque, ↑ muscular endurance, ↑ thigh circumference, ↑ elevated CK (indicator of muscle injury). The more acute subject stopped training due to muscle spasms.

• One subject progressed to the planned stage of FNS-assisted ambulation training.

Belanger et al. 2000; Canada
Downs & Black = 10
Pre-post
N=14

Population: 14 males and females; age 23-42 yrs; 2 incomplete, 12 complete lesions; C5-T5 lesion level; 1.2-23 yrs post-injury
Treatment: Bilateral functional electrical stimulation to quadriceps combined with isokinetic resistance training on left side and unresisted on right; 5 days/week, 24 weeks; each session was 1 hr or until fatigue
Outcome Measures: knee torque, endurance

• Average increase in knee extensor muscle torque on resisted side was 150% (average 8.1% increase/week)
• Average increase in knee muscle torque on unresisted side was 75% (average 4.5% increase/week)
• No change in endurance (fatigability)

Kagaya et al. 1996; Japan
Downs & Black = 9
Pre-post
N = 5

Population: 5 males; age 19-68 yrs; with complete paraplegia (T5-L2 lesion level); 3-60 months post-injury.
Treatment: Subcutaneous PES to various lower limb nerves and muscles for 6 months. Applied at 10 min, 3X/day and gradually increased to 60 min, 3X/day at 10 weeks.
Outcome Measures: Muscle cross-sectional area (CT scan), manual muscle test, stimulated muscle torque.

• No group statistical analysis performed, limited by heterogeneity across subjects.
• All cross-sectional muscle areas except gluteus maximus increased (p<0.05 to <0.001).
• Muscle torques generally increased after PES.
• Manual muscle tests generally increased (p<0.001) for muscles that initially graded as poor-minus (no voluntary movement against gravity).