Postoperative Electrical Muscle Stimulation Two

The main objective of this trial is to assess whether neuromuscular stimulation (NMES) can minimise muscle loss following abdominal surgery for cancer; and whether such effect is further improved by simultaneous protein supplementation. The main questions it aims to answer are: * Does NMES training reduce the volume of muscle lost from the vastus lateralis (VL) muscle (in the thigh) after surgery as measured on ultrasound scan 5 days after surgery? * Does NMES training together with protein supplementation lead to greater reduction of VL muscle volume loss on ultrasound 5 days after surgery then NMES alone? Researchers will allocate participants into three groups (using a randomisation software). All participants will visit the hospital once before surgery for starting point measurements including ultrasound. Whilst they are in hospital, from the first until the fourth day after surgery, they will have the following interventions: * Group 1 (the control group) will receive usual post-operative care with no additional interventions; * Group 2 will receive normal postoperative care and twice daily NMES training sessions and a flavoured (placebo) drink * Group 3 will receive normal post operative care as well as twice daily NMES training sessions and two protein rich drinks per day. On the fifth day after surgery all participants will have repeat measurements including ultrasound to assess the extent of muscle loss they had since surgery.