## 2 Current Prehabilitation Programs
### Prehabilitation Program Parameters  
Prehabilitation programs are designed to improve aerobic fitness and reduce postoperative complications. To achieve this, key exercise parameters were developed. These include the mode, intensity, frequency, duration, and volume of exercise. It is important for a healthcare system to identify and monitor these key exercise parameters to ensure the patient is working at a level of physical activity that will improve physical fitness and reduced perioperative risk. Identifying and logging these parameters can be done through the application of simple wearable technology. Identification of the type of activity the patient is engaging in can provide the therapist with information about exercise modality preferences within clinical and community settings. Aerobic exercise is the most common type of exercise used in cancer prehabilitation programs. Common modalities used in supervised prehabilitation programs include rowing machines, cycle ergometers, treadmill walking, running, and cross training machines [4; 5; 18; 19]. Unsupervised programs tend to be restricted to modes of exercise that are most readily available in the community and include walking, running, and cycling [8; 9]. Different modes of exercise can be identified by using Fast Fourier Transformation (FFT) amplitude and frequency measures of data attained from 3D accelerometers during the activity [12] (Table 1). For example, cycling produces frequency and amplitude values that differ from rowing. This makes it relatively easy to distinguish between the two modalities. A major exercise parameter that has been shown to influence physical fitness and postoperative outcomes in cancer patients is exercise intensity. In prehabilitation programs, exercise intensity is typically describe as \"low\", \"moderate\", or \"high\" and is often quantified as a percentage of maximal heart rate or perceived effort using [PERSON]'s ratings of perceived exertion (RPE). A number of researchers recommend that elderly people perform physical exercise at moderate to vigorous intensities rather than at a light intensity [15; 20; 21]. In addition, it is important to train at moderate exercise intensity becausethis level of activity is associated with greater health benefits and lower mortality risk than low intensity [22]. Most cancer rehabilitation studies have exercised patients at moderate to vigorous exercise intensity, as this has been shown to lead to greater improvements in aerobic fitness when compared to low intensity exercise [15; 20; 21]. In most supervised rehabilitation programs, exercise intensity is quantified using heart rate measures. For example, [PERSON] et al. [4] exercised their patients at 60% of maximal heart rate (moderate intensity), whereas [PERSON] and [PERSON] used exercise intensities that were classified as moderate to vigorous (60-85% of maximal heart rate) [5; 19]. Intensity measures in non-supervised programs are more varied (Table 1). [PERSON] et al. [8] used both heart rate and RPE measures to quantify aerobic exercise intensity in 38 cancer patients of different ages partaking in a non-supervised rehabilitation program. The exercise intensity initially started at 40% of heart rate reserve (low intensity) and gradually increased once the participant was able to complete 20 min of continuous aerobic activity. [PERSON] et al. [9] recruited 22 cancer patients who were scheduled for surgery. In this study, the patients were not given specific intensity measures but were instructed to walk more than five thousand steps each day. More recently, prehabilitation programs have used high intensity interval training (HIIT). HIIT involves a series of short high intensity bouts of exercise (15 s to 4 min duration) followed by a low intensity or rest period.