Lightweight high reps or heavyweight low reps?

I've been involved in sport since I was 8yrs old from being told by my football coach this is not the sport for you pick something else (he wasn't wrong) to which I played rugby up till I was 18 then on off till I was 24, and then a few in my 30s and now regularly at 45. Also since my 30s ive been a competitive powerlifter and all round weightlifter. During this time I have been a sports coach in various sports and a PT instructor for the last 23yrs and a strength coach the last 6yrs.

So I guess what I'm trying to say is I've been around a lot of sport have a lot of experience through my own training, coaching others and seeing how others train.

And one thing that comes up a lot is.

I want to loss weight/tone up but not bulk up, so should I do low weight high reps or heavy weights low reps?

I'm not one to use fancy text book words so I'll keep it simple.

Most PT instructors will have you basically train like a bodybuilder which is basically your standard low/medium weight and high reps and tell you by keeping the weights light you won't bulk up and you'll burn more calories/fat. Some will also chuck you on a treadmill although nowadays most will use sleds, battle ropes, tyre flips as part of your cardio which is much better for you. Not saying a treadmill can't be used but some can over use them.

In theory this sounds great. But the truth is this is not ideal. Because you only need to look at any bodybuilder male or female and see this will pack on size. Now you could argue it all depends on your diet and yes this can play a part to whether you'll gain size or not. And you could say yeah bodybuilders are on gear/drugs but it also comes down to the way they train. Easiest way I could explain this is think as your muscles as a balloon the more reps you do the more blood you are pumping in to the muscle and there for making them bigger. Regardless of what weight you use. You could go really light and crazy high reps but what's the point your just wasting time. Instead keep the weight heavy enough to do 5-8 reps 3-5 sets with this way you will still burn the calories, but also strengthen the muscle as well as your bones without pumping them with too much blood that they grow in size so now you will get toned without building too much size.

You only need to look at a top bodybuilder, powerlifting or crossfit and weightlifter and you can see the difference. You may argue powerlifters are big but how much body fat do they have. Look at ones that have low body fat % then you will see the difference. And Big muscles don't always mean stronger muscles. So when picking your sets and reps think about what is your goal do you want to be big or do you want to be lean. Both can get you strong.

Also The reason I mentioned the treadmill earlier is because to many people use this to loss weight and tone up. The problem with this is because your using no resistance your tell the body you don't need your muscles and because your body will want to make it as light as possible to protect your joints it will get rid or use the muscle as a fuel that's why marathon runners look the way they do. For cardio your best doing interval training short fast bursts like sprints. Or do sled pulls, tyre flips, farmers walk this way your telling your body we need to keep the muscle so use the fat stores first.

I hope this all made sense I'm bit of a waffle and tried to keep it simple so everyone can understand. Any questions just leave a comment

Thanks for reading.