Q: im about to start one of your suggested low volume weight routines, but because of me being overweight and under-powered (not for long!) i cant do pull-ups. is it ok for me to substitiute these with machine pull-downs?

A: Absolutely! Pulldowns pretty much mimic the pullups exactly and are a perfect substitute. Remember to maintain proper upright posture while doing pulldowns: only your arms should be moving, the rest of your body should be motionless. Do not do pulldowns behind your head, only to the chest. Feel free to use either the wide overhand or close underhand grips when doing pulldowns or alternate them. If you want to stick with just one grip, go with close underhand grip. And don't forget to test your strength doing actual pullups -- it won't take you long, especially if you're losing weight at the same time! Good luck!