This is a huge topic today with people who weight train regularly. Although the majority of weightlifters use both, is one better than the other? If so, which one should we be using more frequently and why?
First off, training with free weights such as dumbbells or barbells allows the body a much wider range of motion for most exercises. For example if you are doing a seated shoulder-press with a barbell, you can get the full stretch on the eccentric motion without the bar being locked into a vertical plane like a machine shoulder-press is. Yes, while doing a shoulder press you should, in theory, not be moving the bar front to back, but that is where your stabilizing muscles come into play. Recruiting your stabilizing muscles and being able to control the weight is crucial when it comes to any strength gains. When doing the shoulder press on the machine with a weight stack, the stack of weights is locked in on a vertical plane and doesn’t allow any front to back movement, which in turn can lead to weaker stabilizing muscles.
Training with machines can also lead to muscle imbalances, or an alteration of muscle length surrounding a joint. It’s not uncommon for the dominant side of the body to take over and produce more force when training. This means that one side of the body is stronger than the other. Utilizing free-weights such as dumbbells allows you to correct these imbalances by training the weaker side to keep up with the stronger side.
Machine weights do have their benefits though. One of them being tension. Using a machine with a weight stack will allow you to have tension on the targeted muscle throughout the entire range of motion. For example if you are doing a seated chest press, the handles and weight stack are designed in such a way that it will keep tension on the chest through the eccentric and concentric movements. Cable movements are also a great way to keep that tension on the muscle. Doing exercises such a chest flys with the cables will keep more tension on the chest rather than with dumbbells, ultimately leading to a more defined, and developed chest.
Both styles of training have their benefits, but overall if you are looking to gain strength, and size, I suggest using free-weights. If you are looking to have more definition and are just training to maintain your overall physique and health, machine weights and cables will do the trick.
-Joey at DyeHard