How hot do your muscles get during intense exercise?

Each participant is to attend 1 familiarisation and 3 sessions consisting of combined resistance exercise (RE) and high-intensity interval exercise (HIIE). Sessions to be 1 to 4 weeks apart per participant, and standardised for time of day within participants, and no strenuous exercise beforehand on each day. The intervention consists of measuring muscle, core (oesophageal and rectal) and skin temperature responses to 3 different profiles each of unilateral RE and HIIE. RE and HIIE to occur in the same session, with RE first because it has the least thermal effect so baseline oesophageal temperature is reattained more quickly (15-30 min between finishing RE and starting HIIE). RE: 3 unilateral bicep curl RE sessions each with a different protocol: strength, hypertrophy and endurance. Order of sessions for each participant at investigators' discretion but will attempt to randomise. Strength (1RM) to be determined in a familiarisation session, and used to allocate the intensity for each RE session as follows: A. Strength: 6 sets of 6 repetitions @ 85% 1RM B. Hypertrophy: 3 sets of 10 repetitions @ 70% 1RM C. Endurance: 3 sets of 30 repetitions @ 35% 1RM Rest between all sets will be approximately 2 min. HIIE: 3 HIIE single-leg cycle sessions using electromagnetically-braked cycle ergometry of the ipsilateral lower limb. Order of sessions for each participant at investigators' discretion but will attempt to randomise. Peak power output (PPO) will be determined in a familiarisation session using incremental exercise to exhaustion. The intensity for each HIIE as follows: A. 10 x 1 min intervals @ 95% PPO with 1 min recovery between intervals B. 3 x 4 min intervals @ 80% PPO (or maximum sustainable intensity if unachievable), with 3 min recovery between intervals C. 15 min continuous exercise at 65% PPO (or maximum sustainable work rate if this becomes too high). Measurements: Muscle temperature with needle and in-dwelling thermocouples administered by supervisors (Drs Kate Thomas and Jim Cotter) who are experienced in these measurement procedures. Core (rectal and oesophageal) and skin temperatures with thermistors administered by two MSc students (Tom de Hamel and Ben Smith). These trials will be undertaken on each of 4-5 participants (dependent on availability of volunteers, as this is only a pilot study for a training study).