Patients lose a significant amount of muscle following major abdominal surgery. This is partly due to a catabolic response to the surgical insult and inflammation, but is also probably due to a lack of muscle use secondary to immobility.

This study will aim to assess whether some or even all of postoperative muscle loss in the upper leg muscle group is preventable through electrical muscle stimulation to mimic physical activity.

Following major gastrointestinal surgery patients may loose around 6 % of their skeletal muscle mass in the first 5 days. Whilst some of this loss is as a result of inflammation and starvation, some is due to muscle disuse.

Studies have shown that patients spend 96% of their time being sedentary in the first 5 days following major abdominal surgery and by day 5 are still taking a median of less than 500 steps per day. Studies of healthy volunteers who undergo similar muscle disuse loose approximately 3.5% of skeletal muscle mass over the same time period, indicating that around half of postoperative muscle loss may be due to immobility.

Through the use of electrical muscle stimulation, this study will aim to mimic high levels of exercise in the quadriceps of patients who have undergo major gastrointestinal surgery to see whether this reduces or prevents muscle loss. Patients muscles will be measured using ultrasound and DXA and neuromuscular function will be measured using electromyography.

Inclusion Criteria:

• Adult patients undergoing major segmental colonic resections or gastric/oesophageal resection
• Sufficient mobility and fitness to complete normal enhanced recovery protocols following surgery
• Ability to give informed consent

Exclusion Criteria:

• Pre-existing neuromuscular disease (including parkinson's disease)
• Pacemaker, implantable cardiac defibrillator or other implanted nerve stimulator device
• Metalwork in both upper legs
• Dementia
• Inability to give informed consent
• Disability preventing normal mobilisation after surgery
• Symptomatic peripheral vascular disease
• Chronic kidney failure of chronic heart failure
• Intubation for > 24 hours post operation
• Return to theatre for surgical complication within first 5 days post operation

No plan to share individual participant data

ultrasound images, DXA scans and EMG results will be given coded labeling by a separate researcher so that investigator analysing results will be blinded to whether scans / EMG results are from intervention or control leg, or start of finish.