Is a homemade barbell with the weights in the middle of the barbell just as effective as a barbell you'd find at a gym?

[Florida2014]

Is it better than nothing? Sure. But this is not a substitution for real weights. To continue to gain strength you're going to have to keep adding weight and I don't see how that's possible with a flimsy backpack. Plus you're very limited in what you can do with that and my guess is if you don't have perfect form it's going to lead to injuries.

Do you live near a Planet Fitness? I'm not a fan of their gyms but you can join one for like $10/mo now. That's certainly better than a stick with a backpack.

[rabbit33]

How broke are you, really, OP? Even someone really on their uppers can make a Travis Bickle barbell. Plates and bars are available used for short money. A 8 foot 1 x 12 and some angle brackets make a bench.