Background: Gameful design has been shown to have the potential to increase motivation for and engagement with physical activity (PA). However, at present, there is a significant lack of well-designed frameworks identifying effective pathways to increase PA behaviour. Purpose: To design a rigorous, methodologically sound, theory-grounded framework for developing gamefully designed PA interventions. Methods: Intervention Mapping (IM) was used to develop the study protocol, consisting of three studies. Study 1 encompassed the design of a novel theoretical framework leading to the selection of a gamefully designed PA intervention application. Study 2 entailed the intervention implementation. Participants (n = 83; mean age = 33.56; females = 48) were randomised to a six-week intervention. Data collection over a six-month period included biometric data, objective measurement of moderate-to-vigorous PA (MVPA) and a detailed PA motivation inventory. Study 3 presented a process evaluation focused on usefulness, effectiveness and feasibility via a systematic mixed-methods approach. Results: Study 1 led to the creation of a new Taxonomy of Situated Motivational Affordances (SMAs) for Gameful Design, the establishment of selection criteria for gamefully designed PA applications and the selection of a commercial application (Fitocracy) for the example case pilot intervention. Study 2 showed no statistically significant change observations in relation to MVPA; however, at six weeks the intervention group showed significant increased levels of identified regulation (internalised motivation) for PA. A significant correlation (p=0.031) between intrinsic regulation and MVPA was verified. Study 3 determined the usefulness of a systematic methodological study design, a low adoption rate of the intervention application and the appreciation of the complex nature of human motivation in relation to PA. Conclusions: Gamefully designed applications grounded in theories such as SDT, BCTs and the newly developed Taxonomy of SMAs for Gameful Design have the potential to be effective in impacting motivation for PA and PA levels.

Acetylcholinesterase inhibition with pyridostigmine has been previously studied in patients with congestive heart failure (CHF), but the effects of this medication on heart rate recovery after exercise and other indices of parasympathetic activity in populations with greater baseline vagal tone has not been fully characterized. Ten healthy, sedentary adults and ten aerobically trained athletes were enrolled in a prospective, double blind, randomized placebo controlled crossover trial. All study subjects were treated with a single dose of oral pyridostigmine 30 mg and matching placebo on separate days. Heart rate variability (HRV) at rest and heart rate recovery (HRR) at one minute after maximal cardiopulmonary exercise stress testing were measured. In sedentary adults, pyridostigmine significantly lowered resting heart rate (mean (SEM) 58.1 (2.4) beats/min versus 66.7 (4.0) beats/min, p = 0.01), increased HRR at one minute (45.1 (2.8) beats/min versus 40.7 (3.4) beats/min, p = 0.02), and lowered both resting mean arterial pressure (80.3 (2.0) mm Hg versus 84.3 (2.7) mm Hg, p = 0.02) and peak exercise mean arterial pressure (103.3 (3.1) mm Hg versus 108.8 (3.2) mm Hg, p < 0.01). In trained athletes, resting heart rate and HRR at one minute were unaffected by pyridostigmine dosing, although a significant increase in VO2 max was observed with the study drug (54.8 (3.5) ml/kg/min versus 53.3 (3.6) ml/kg/min, p = 0.02). Pyridostigmine did not change indices of heart rate variability in either cohort. The difference in resting heart rate and HRR responses to pyridostigmine between athletes and sedentary controls likely reflects training induced modifications of the autonomic nervous system. The inability of acetylcholinesterase inhibition to affect HRV in either sedentary adults or athletes further suggests the improved HRR previously observed in CHF patients treated with pyridostigmine is secondary to parasympathetic augmentation.

There is growing appreciation of the potential for high intensity interval training (HIT) to rapidly stimulate metabolic adaptations that resemble traditional endurance training, despite a low total exercise volume. However, much of the work has been conducted on young active individuals and the results may not be applicable to older, less active populations. In addition, many studies have employed "all out", variable-load exercise interventions (e.g., repeated Wingate Tests) that may not be safe, practical or well tolerated by certain individuals. We determined the effect of a short program of low-volume, submaximal, constant-load HIT on skeletal muscle oxidative capacity and insulin sensitivity in sedentary middle-aged individuals who may be at higher risk for inactivity-related chronic diseases. Sedentary but otherwise healthy men (n=3) and women (n=4) with a mean (±SE) age, body mass index and peak oxygen uptake (VO_2peak) of 45±2 yr, 27±2 kg-m^2 and 30±1 ml·kg^-1·min^-1 were recruited. Subjects performed 6 training sessions over 2 wk, each consisting of 10 x 1 min cycling at 60% of peak power elicited during a ramp VO_2peak test (<90% of heart rate reserve) with 1 min recovery between intervals. Needle biopsy samples (v. lateralis) were obtained before training and <72 h after the final training session. Muscle oxidative capacity, as reflected by the maximal activity and protein content of citrate synthase, increased by ~20% after training, which is similar to changes previously reported after 2 wk of Wingate-based HIT in young active subjects. Insulin sensitivity, based on fasting glucose and insulin, improved by ~35% after training. These data support the notion that low-volume HIT may be a practical, time- efficient strategy to induce metabolic adaptations that reduce the risk for inactivity-related disorders in previously sedentary adults. / Thesis / Master of Science (MSc)