Exercise Impact on Dietary Protein Efficiency in Older Adults With Type 2 Diabetes

1. Enrollment, Informed Consent, and Screening Questionnaires: Prior to study enrollment, participants will be asked to read a digital copy of an informed consent document provided using the e-Consent framework through the Research Electronic Data Capture (REDCap) system. Should participants have any questions about the study after reading the document, they will be encouraged to contact the research team prior to providing informed consent. Upon providing informed consent, participants will receive an email containing questionnaires designed to assess study eligibility via REDCap. Specifically, participants will be asked to complete a health and medical history questionnaire, physical activity readiness questionnaire (PARQ), International Physical Activity Questionnaire Long Form (IPAQ), and Godin-Shephard Leisure-Time Physical Activity Questionnaire (LTPAQ). Information from the questionnaires will be used to assess exclusion criteria, and the IPAQ will be used to assess baseline habitual activity level. Upon completion of these questionnaires, the research team will review the responses and determine eligibility.
2. Preliminary Testing Day 1:

2.1 Preparation: Participants will arrive for the preliminary testing session after an overnight fast (~10 h no caloric foods/beverages consumed) and having refrained from exercise for the 72 h prior.

3.2 Cardiorespiratory fitness assessment: Peak aerobic capacity and maximum heart rate (HR) will be estimated using a submaximal graded stationary bicycle exercise test. Briefly, participants will pedal for 3 minutes at a resistance of 0kg, maintaining a cadence of 50 as a warm-up. Then, the investigators will have the participant pedal for 3-4 minutes, or until a steady state is reached, at 0.5kg, maintaining the same cadence. Resistance is increased every 3-4 minutes until the participant reaches 85% of age-predicted maximal heart rate (220-age).

3.3 Muscle Performance (1RM and power Testing): maximum strength will be assessed using a 10-repetition max (10-RM) on a leg extension, leg press, leg curl, chest press, shoulder press, seated pulldown, and seated row machines. Following a 5-minute warm-up on a stationary bike at a self-selected resistance and speed, participants will perform a set of 8-10 reps at around 50% of what they think they can lift 10 times. 1-2 minutes of rest will be given between each try. The next set will be around 90% of what the participant believes they can lift ten times. investigators will gradually increase the weight by 2.5-5.0% at a time until the participant can no longer lift it. A two-minute rest will be provided between the maximum number of attempts and between exercises.

3.3.5 The HUMAC NORM Isokinetic Dynamometer (CSMi, Stoughton, Massachusetts) will be used to assess peak torque, average workload, and average power in concentric tests and maximal voluntary contraction (MVC). Each participant will be seated upright, with the knee bent. The shank of the dominant leg will be secured to a padded, rigid metal bar using a Velcro strap. With standardized verbal encouragement, participants will perform brief maximal voluntary isometric contractions (MVC), separated by at least 60 seconds of rest, to determine maximal knee extension torque. Maximal power of the knee extensor muscles will be obtained at several test velocities using 2 sets of 4 maximal isokinetic knee extensions, including at a velocity of 60 deg/s. Strong verbal encouragement will be provided to kick as hard and as fast as possible throughout the full range of motion for each velocity. Participants will rest for at least 60 seconds after each set of 4 contractions to minimize muscle fatigue during the power assessment.