I can say from personal experience that not everyone in the gym knows what they’re doing. A lot of them (read: us) haven’t the faintest clue whether our overall fitness and longevity benefit most from fewer reps of heavier weights or more reps of lighter ones, for example. That’s why I reached out to physiotherapist and author Kieran Sheridan for his insights regarding the overall health benefits of lifting a few heavy weights at the gym versus doing many reps of lighter weights. Based on my own personal preferences and fitness goals, I now know which one works best for me. Do you? Physiothera…