Heat, sweating, and World Cup banter 07:40 What rep ranges actually build muscle? 12:30 The effective 4-to-50-rep range and muscle fiber types 15:50 Can you tell whether you are fast-twitch or slow-twitch? 21:56 Fiber types in sports, bodybuilding, and powerlifting 26:01 Why 4 to 12 reps has a practical advantage 29:07 Volume, proximity to failure, and stretch matter more 35:02 Matching rep ranges to pain, experience, and exercise selection 39:02 How to train for strength and muscle growth together 44:42 High reps versus heavy sets: physical and psychological fatigue 49:47 What the fatigue research shows and the final recommendations