For athletes with training experience, the 6 day split is an effective approach to building muscle. Previous training experience provides the body with a good training base to undergo the 6 day split. I would only recommend the 6 day training split for advanced lifters. It’s also important to take your recovery seriously. If you’re not recovering properly your performance in the gym will drop and your progress will be stunted. Intense exercise like the 6 day split is unsuitable for untrained individuals,. If you’re new to training, start with a 2-3 day split. Build up your tolerance to your exercise before increasing your frequency. If you're brand new to exercise I would also recommend starting with bodyweight exercises only. For successful training, it's important to find which training volume suits you.