• FES-assisted cycling

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 or 3) control group (n=9) with no stimulation.
Outcome Measures: lower limb lean body mass.

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

Duffell et al. 2008;
UK
Downs & Black = 16
Prospective Controlled Trial
N = 11

Population: 11 subjects with complete SCI, level of injury T3-T9, 10.7+2.1 YPI; 10 untrained AB controls, mean age 30.6+3.2 yrs
Treatment: FES cycling, up to 1hr/day, 5 days/week for 1 year
Outcome Measures: Maximal quadriceps torque; quadriceps fatigue resistance; power output (PO).

• The maximal quadriceps torque increased significantly throughout training in SCI subjects (+399% at 3 months, +673% at 12, p=0.012), but remained significantly less than that of AB controls (107.0+17.9 vs. 341.0+28.6).
• Quadriceps fatigue resistance (76.7 + 2.0% force loss after 3 min at baseline, compared to 30.3+4.6% after 12 months) and peak power output (+177%) improved significantly after training.

Scremin et al. 1999; USA
Downs & Black = 16
Pre-post
N=13

Population: 13 males; age 24-46 yrs; AIS A; C5-L1 lesion level; 2-19 yrs post-injury.
Treatment: A 3-phase, FES-assisted cycle ergometry exercise program leading to FES-induced cycling for 30 minutes. Average program was 2.3X/week for 52.8 weeks.
Outcome Measures: CT-scan of legs to assess muscle cross-sectional area and proportion of muscle and adipose tissue collected (pre-test, midpoint and post-test).

• ↑ cross-sectional area including: rectus femoris, sartorius, adductor magnus-hamstrings, vastus lateralis, vastus medialis-intermedius (all p ≤ .025). No change in cross-sectional area of adductor longus and gracilis muscles.
• No correlations between total number of sessions and magnitude of muscle hypertrophy.
• Significant increases in the muscle/adipose tissue ratio (p<0.05), muscle tissue in the thigh and leg (p<0.05) but no changes in the adipose tissue.

Janssen & Pringle 2008;
The Netherlands
Downs & Black = 15
Pre-Post
N = 12

Population: All subject are male, 6 subject with tetraplegia and 6 with paraplegia, including 4 subjects (age 44 + 14, yrs post-injury 13 + 8) who had previous training on ES-LCE.
Treatment: Computer controlled electrical stimulation induced leg cycle ergometry (ES-LCE); total of 18 training sessions with each session lasting 25-30 minutes.
Outcome Measures: Heart rate; power output; oxygen uptake (VO2); Carbon dioxide production (VCO2); pulmonary ventilation (Ve); peak torque.

• Significantly higher heart rate (+16%) and power output (+57%) after training, compared to baseline
• Significantly higher peak values for VO2 (+29%), VCO2 (+22%), and Ve (+19%)
• Peak torques were significantly higher for most of the relevant muscles

Gerrits et al. 2000; UK
Downs & Black = 14
Pre-post
N=7

Population: 7 males; age 28-61 yrs; AIS A and B; C5-T8 lesion level; 1-27 yrs post-injury
Treatment: FES leg cycle ergometry training, 3 - 30 minutes sessions/week for 6 weeks.
Outcome Measures: Thigh girth, work output, contractile speed and fatigue resistance characteristics, including half relaxation time (½ Rt) and degree of fusion of electrically stimulated isometric contractions.

• ↑ Work output as training progressed (p=0.019).
• More fatigue-resistant: ↓ force decrement during quadriceps fatiguing stimulations (p=0.012).
• No change in contractile speed (using maximal rate of rise force) but half relaxation time decreased (p=0.014) and there was significantly less fusion (p=0.006).
• ↓ Force responses at low stimulation frequencies, indicating less fusion and more relaxation.
• No change in thigh circumference.

Koskinen et al. 2000; Finland
Downs & Black = 14
Pre-post
N=10

Population: 10 males and females; age 27-45 yrs; complete; tetraplegic and paraplegic
Treatment: 18-month FES-assisted cycling ergometry (First training period: 30 min, 3X/week, 1 year; Second training period:1X/week, 6 months).
Outcome Measures: Muscle morphology and protein measurement (type IV collagen, total collagen, muscle proteins).

• Total collagen content (as indicated by hydroxyproline concentration) was increased with first training period (p=0.05) and second training period (p=0.05) and even more so compared to able-bodied controls. No difference in Type IV collagen content between groups.
• This result combined with the changes seen with the other muscle proteins suggest accelerated type IV collagen turnover in skeletal muscle.

Liu et al. 2007; Taiwan
Downs & Black = 12
Pre-post
N=18

Population: 18 males and females; age 26-61 yrs; AIS B-D; C3-L1 lesion level; 1-9 yrs post-injury
Treatment: Functional electrical stimulation cycling exercises three times a week for 8 weeks; 30 minutes/session
Outcome Measures: Muscle peak torque of knee flexors and extensors

• Significant ↑ in mean thigh girth after 4 weeks
• Significant ↑ in peak torque of bilateral knee flexors and right knee extensors
• Strength gains in AIS D > AIS C > AIS B

Crameri et al. 2002; Denmark
Downs & Black = 11
Pre-post
N=6

Population: 5 males, 1 female; age 28-43 yrs; complete; T4-T12 lesion level; >8 yrs post-injury
Treatment: FES leg cycle ergometry training, 3 - 30 min/week for 10 weeks.
Outcome Measures: Incremental exercise leg test to muscle fatigue (total work output), histological assessment, myosin heavy chain (contractile protein) (MHC), citrate synthase (a mitochondrial enzyme) and hexokinase (enzyme needed to produce muscle glycogen).

• Total work performed increased (p<0.05) after training.
• Paralysed vastus lateralis muscle was altered with ↑ type IIA fibres, ↓ type IIX fibres ↓ MHC IIx and ↑ MHC IIA (p<0.05).
• Total mean fibre cross-sectional area increase of 129%, ↑ cross-sectional area of type IIA and IIX fibres (p<0.05).
• ↑ Number of capillaries surrounding each fibre (p<0.05).
• ↑ Citrate synthase and hexokinase activity (p<0.05).

Haapala et al. 2008;
USA
Downs & Black = 11
Pre-Post
N = 6

Population: 6 SCI subjects, between 20-50yrs old, complete and incomplete injury at or below C4, with previous FES cycle ergometry experience.
Treatment: FES-LCE, progressive cycling (resistance) protocol with increasing resistance, as well as prolonged, submaximal cycling for 30min.
Outcome Measures: Power output for ankle (APO), knee (KPO), and hip (HPO), HR

• 4 subjects successfully completed both protocols.
• Initial and final APO for progressive protocol was lower than the submaximal protocol, but was not significantly different. There was no significant change in APO in the progressive protocol. APO significantly declined with time in the submaximal protocol.
• The initial KPO were similar for both progressive and submaximal protocols. There was no significant change in KPO during the progressive protocol. KPO significantly declined with time in the submaximal protocol.
• HPO for progressive protocol increased significantly with resistance. HPO for the submaximal protocol varied over time but displayed a gradual decrease overall.
• HR was initially similar for both protocols. HR for submaximal cycling increased significantly with time. There were no significant changes in HR during the progressive protocol.

FES-assisted Stand or Gait Training

Carvalho de Abreu et al. 2008, 2009;
Brazil
Downs & Black = 17
Prospective Controlled Trial
N = 15

Population: 15 complete chronic subjects with tetraplegia (injury level C4-C7, mean age 31.95 + 8.01 yrs) with intact lower motor neurons, divided into gait training (n=8) and control (n=7) groups
Treatment: Partial body-weight supported treadmill gait training with neuromuscular electrical stimulation (NMES), for 2 - 20min session every week for 6 months; control group performed conventional physiotherapy, and gait training without NMES for 6 months
Outcome Measures: Cross-sectional area (CSA) of quadriceps, muscle hypertrophy.

• After gait training there was a significant increase in quadriceps CSA (49.81+9.36 cm2 vs. 57.33+ 10.32 cm2), whereas there was no significant difference in the control group.
• No significant differences in muscle mass after 6 months, but the NMES group increased by 7.7%, and the control group decreased by 11.4%.

Kern et al. 2005; Austria
Downs & Black = 14
Pre-post
N=9

Population: 1 female, 8 males; age 20-49 yrs; complete traumatic conus cauda equina lesions; > 0.8 yrs post-injury.
Treatment: Progressive PES to FES program for quadriceps to FES-assisted standing (n=4 trained ³ 2.4 years); untrained controls (n=5).
Outcome Measures: Muscle biopsy of vastus lateralis (mean fiber diameter, % area covered by muscle fibers, adipocytes, connective tissue).

• Overall mean fiber diameter of trained group was increased vs untrained group (p<0.001) and also had similar values to normal sedentary adults.
• Proportion of total cross-sectional area covered by muscle fibers increased with training whereas the area covered by adipocytes and connective tissue significantly decreased.