NO

says Jesse La Flair, stuntman and pro freerunner who directed and starred in parkour documentary From Here To There

Muscles are built to work together. In real life, you will rarely ever need just one muscle to fire so it makes no sense to train them to do that. Isolation exercises can be useful for rehabilitation, and if your body naturally favours one side and the other needs to catch up, but in my opinion it’s simply insane to spend time doing them just for the purpose of looking a certain way.

When I first started freerunning I was scrawny with a lack of control and balance. While I’m not totally jacked, nowadays I’m cut, functionally strong, and more agile than ever – and I don’t do isolation exercises in my training.

Some people see ripped guys with big arms and shredded six-packs, and think the only way to look like that is by going to the gym and doing endless crunches and biceps curls. For me, those kinds of isolation exercises are boring and smell of desperation. You can still be in incredible shape without ever setting foot in the gym. I train and play in various freerunning facilities and outdoor training spots literally all over the world, and I still have the strength to do one-finger pull-ups.

Unless you have a burning desire to cover yourself in baby oil and flex your muscles in front of a crowd of strangers while wearing a thong, don’t waste your time on isolation exercises. Just get outside and move.

I'm constantly finding different ways to engage my body and mind by overcoming the challenges that I set for myself. Yeah, I’m in decent shape, but most importantly I’m having a lot of fun.

fromheretotheredoc.com

‘ENDLESS ISOLATION EXERCISES ARE BORING’