## 2 Current Prehabilitation Programs
### Prehabilitation Program Parameters
The advantages of this type of training are that patients are able to sustain high intensity workloads over short time periods in the initial stages of prehabilitation, and a similar volume of exercise can be achieved in a much shorter duration of time when compared to continuous exercise at a moderate intensity. HIIT has also been shown to achieve similar or greater improvement in aerobic fitness when compared to moderate intensity continuous training [23]. Heart rate monitoring is relatively easy to use as a measure of intensity when exercise is performed under the supervision of a quality health professional. However, the use of heart rate measures in the community is more difficult due to the complexity of attaching heart rate monitors, administration of heart rate altering drugs, and the difficulties associated with downloading heart rate data. It is also difficult to determine the type of activity being performed when using heart rate and RPE measures. A more recent approach used to detect the intensity of a specific type of activity is 3D accelerometry. Different activities at a particular intensity will produce specific amplitude and frequency measures. For example, for older people, walking at a low intensity (3.5 kph) will produce lower frequency and amplitude measures than walking at a high intensity (4.5 kph) [12]. The frequency and duration of prehabilitation exercise interventions are also important parameters that need to be monitored. Most supervised and unsupervised prehabilitation programs require patients to exercise for a minimum duration of 20-30 min two to seven times per week. For example, [PERSON] et al. [5] involved 115 participants under the supervision of physiotherapist for six weeks. Exercise was undertaken on a cross trainer, rowing machine, and stationary bike for a duration of 20-30 min five times per week at a moderate to vigorous intensity. [PERSON] et al. [18] investigated the postoperative effect of a supervised prehabilitation exercise program on 41 colorectal cancer patients. The exercise prescription was personalized to each participant's fitness level. Participants were prescribed 30 min of moderate intensity aerobic activity consisting of either walking, cycling, or jogging three to four days per week. [PERSON] et al. [15] suggests that exercise bout duration should at least be 10 min to have a significant physiological effect. Multiple 10-15 min bouts of exercise at a moderate to vigorous intensity have been shown to be as effective as 30 min of continuous moderate intensity exercise for improving aerobic fitness in deconditioned individuals [15; 22]. A prehabilitation model IOT system must be designed to identify and detect these short bouts of physical activity. Furthermore, sample rates of accelerometers must be high enough to detect the repetitive short burst of high intensity activity followed by low activity or rest that occurs during HIIT. Our previous research showed that 3D accelerometer FFT analysis had the potential to accurately identify type and intensity of exercise over relatively short periods of time [12]. The volume of exercise provides the clinician with an indication of total amount (volume) of exercise or energy expenditure and is a product of the intensity, duration, and frequency. It has been shown that exercising at a vigorous intensity for 20 min three times per week produces a similar volume of exercise to exercising at moderate intensity for 30 min five times per week. The minimal volume of exercise required to improve pre- and postsurgical outcome measures in abdominal cancer patients has not been clearly established. However, [PERSON] et al. (2018) found convincing evidence that a higher volume of physical activity provided greater health benefits than low volume physical activity in those individuals who were relatively inactive.