Training Q & A: Barbells, Dumbbells, and Machines – Which Do I Use In My Workout And Why? – Part 2

By Lee A. Mancini, MD, CSCS, CSN

In part one of this series I introduced some basic definitions on free weights, barbells, dumbbells, and strength training machines. These definitions were not meant to be all-inclusive. There are many types of free weights and machines that I did not mention. My purpose was not to define every possible weight machine or free weight tool, but rather to lay a basic foundation upon which to build. In this article, I would like to address the pros and cons of each of the different training equipment types that were brought up in part one. However, before we go any further I would like to make two things perfectly clear -

Statement #1 – Doing strength training is better than NOT doing strength training!

Statement #2 – When I design programs for clients of all ages I use barbells, dumbbells, medicine balls, body weight exercises, and machines. Each piece of equipment has its benefits or disadvantages.

Machines – Advantages
You can perform exercises on machines by yourself. If you are lifting heavy weights, there is no need for a spotter to help you if you get stuck. Machines lessen the risk of injury from lifting weights that are too heavy for you to handle and having the weight fall or trap you.

Machines – Disadvantages
Machines restrict your body’s natural movement pattern. For example, if you have ever tried to perform squats on the Smith Machine, you will have noticed that the barbell tracks along the two poles on either side so that the barbell can only go straight up and down with no front or backwards movement. The movement is in only one plane. This is bad for a number of reasons.

First, the human body was meant to function in all three planes. A free weight barbell squat when performed correctly puts the stress of the load on your tibia (shin bone) and your femur (thigh bone), there is little force put directly on your patellafemoral (knee cap to thigh bone) joint. However, when one performs a barbell squat on a Smith Machine, the angles of force are changed due to the restriction of movement in two of the three planes. As a result, studies have shown that nearly all the force is loaded onto your patellafemoral joint instead of your tibia and femur. This is not good because many athletes and adults in general have wear and inflammation under their kneecaps at the patellafemoral joint. There are many other examples of how machine exercises change natural body movement and create a pattern of stress that over time can cause an injury.

Machines have very little or no transfer for athletes to their sport. Whereas medicine balls can improve power and speed, as well as serving to integrate multiple muscle groups into a movement pattern, machine exercises deconstruct movement patterns. Some machines are constructed so the weight has to be moved at a specific speed which forces trainees to lift at a predetermined pace. This means that athletes can not perform speed strength training which is vital towards improving athletic performance. This is also not good for even non-athletes, since including some form of explosive or fast training in your program helps recruit more fast twitch muscle fibers and burn more calories in the long run.

Conclusion

In part one of this series, I also assigned some homework for all of you to perform. You were to have performed without rest one set to failure of each of these exercises: dumbbell flat bench press, barbell flat bench press, and finally machine flat bench press all using the same weight. What you should have noticed is that after you performed as many reps as possible of the dumbbell bench press you were able to perform at least 2-3 more reps on the barbell bench press, and finally another 2-3 more reps on the machine bench press.

Even though all three exercises work your chest, the energy requirements are vastly different for each. The machine bench press is the easiest of the three exercises, while the dumbbell flat bench press is the hardest. The dumbbell flat bench press forces each arm to work independently of the other. This means your stronger arm is unable to compensate for your weaker arm. Also when pressing the dumbbells, you have to balance them in three dimensional space. This incorporates accessory muscles into the movement. The machine press does not force you to move the bar in three dimensional space, nor does it involve your accessory stabilizing muscles. This is why if you are trying to improve athletic performance or lose body fat, dumbbell free weight exercises are the best way to go.

In part three of this series we shall examine the advantages and disadvantages of dumbbells and barbells.

Send any questions or ideas for topics of future interest to questions@DoctorOfFitness.com.

Note:  Lee A. Mancini graduated from Harvard as a two-sport athlete with honors in biology. Board certified in sports medicine and family practice, he works at the Family Health Center and UMass Sports Medicine Center in Worcester . He trains select clients as a certified strength and conditioning specialist and sports nutritionist. If you are interested in hiring him to design an individualized program, click here for our paid consultation services.