NSPA's Personal Training Journal

Free Weights and Machines

Paul Sorace, MS, RCEP, CSCS, CCS

Fellow of the National Board of Fitness Examiners

Introduction

Free weights and selectorized machines seem to be debated endlessly as to which is superior. This debate misses the point. It’s important to understand that while no training modality is perfect, both have unique features that should be understood so personal trainers \ conditioning specialists can make educated decisions when designing resistance training (RT) programs.

Free Weights

Free weights include dumbbells and barbells. Table one summarizes the unique characteristics of free weights.

TABLE 1 Training Features of Free Weights

• Mimic real life movements
• Use of stabilizing muscles
• Wide ranges of motion
• Variety of alternative exercises (dumbbells & barbells)
• Dumbbells offer numerous movement planes & hand positions
• May best accommodate some populations (e.g.-obese, small framed people)

Free weights demand more inter and intramuscular coordination. This means many muscles are required during free weight exercises for balance, stabilization, coordination, and control. Using many muscles together is what makes free weight exercises functional or mimic real life movements. There’s no fixed range of motion (ROM) and the weights are not guided. Therefore, multiple muscles must work synergistically to achieve proper form and technique.

Free weights allow for greater and varying ROMs that can accommodate different body frames. For example, a typical bicep curl machine locks in the arms and shoulders. Anatomical carry angles (lateral deviation of the forearm in relation to the humerus) vary considerably among individuals. For those with a greater lateral deviation, a machine curl may not allow for proper joint alignment. This can overstress the elbow and forearm, leading to elbow and forearm pain. A dumbbell curl allows each individual to follow their natural carry angle and ROM. During the eccentric phase of a dumbbell bench press, the lifter can keep the dumbbells in line with the shoulders. Or he \ she can bring them out wider, beyond the shoulders, altering the ROM.

Movement planes can vary with dumbbells to emphasize different muscle groups. When performing a dumbbell overhead press, the lifter can perform the exercise with their arms out to the sides in the frontal plane to emphasize shoulder abduction. Or, they can keep their arms more in front of their body in the saggital plane to emphasize shoulder flexion. Hand and wrist positions can also be altered with dumbbells, varying the muscles emphasized. Using a supinated grip (palms up) during a dumbbell curl emphasizes the biceps muscle. Changing the wrist position to a mid or hammer grip emphasizes the brachioradialis. This can be significant for those with orthopedic concerns. A slight adjustment in hand position can make all the difference in comfort level. Dumbbell curls can be performed with a supinated, mid (hammer), or pronated grip. The lifter can also start with a hammer grip and rotate to a supinated grip. Other dumbbell exercises enable various and rotating hand \ wrist positions (e.g.- chest fly, bench press, overhead press).

Any barbell exercise has a dumbbell alternative (e.g- bench press, bicep curl). Dumbbells enable a lifter to perform each arm independently. This is beneficial for correcting muscle imbalances and maintaining muscle symmetry. A lifter can perform one limb at a time to better emphasize that side. This is especially useful when different weights are used on each side.

Free weights also enable the performance of structural exercises (e.g.- squat, deadlift). These exercises force the body to fully support the weight plus the individual’s bodyweight and work multiple, large muscle groups. There are a number of machines available that can be performed in a standing position but free weight versions require more overall muscular effort due to the lack of a fixed ROM. Many free weight exercises are or can be performed in a standing position, working the entire body more than a seated position would.

For very small framed or obese individuals, free weights may be best since these individuals may not fit into some machines properly. Certain competitive athletes such as Power lifters and Olympic lifters will train predominantly with free weights since free weights are used during their competitions.

Selectorized Machines

Nautilus, Cybex, LifeFitness, and BodyMaster are a few of the more popular selectorized machines. Table two summaries the unique training features of machines.

TABLE 2 Training Features of Selectorized Machines

• Safety and ease of use
• Fixed range of motion
• Rotational resistance
• Muscle isolation
• Time efficient RT sessions
• May best accommodate some populations (e.g.- elderly)

Machines are safer to use than free weights. You cannot get “trapped” on a machine and you can perform any machine without a spotter. If a lifter fatigues and fails to complete a rep, the weight is simply returned to the weight stack. However, safer doesn’t mean risk free. Proper form and body alignment are still required to maximize safety.

Machines are also easier to learn and perform correctly. The fixed range of motion that machines provide makes proper form more likely. This is particularly beneficial for the novice lifter. Since proper form is essential to prevent injuries, this feature adds to the safety of machine use. Again, this doesn’t mean poor form cannot occur on machines. Uncontrolled rep speeds will increase momentum, which reduces the tension on the working muscles and increases stress on the joints. An improper seat adjustment may overstress the working joint or emphasize muscles other than the intended ones.

Some exercises cannot be worked effectively without a machine. Machines provide varying patterns of resistance that would be very difficult to achieve with free weights. Leg extension and leg curl machines, for example, provide rotational resistance that allows the quadriceps and hamstrings to be worked through a full ROM (from full stretch to full contraction). Rotational resistance provides resistance in a rotary motion. As a result, regardless of what point the working limb(s) is at during a rep, the resistance always directly opposes the working muscles.

To illustrate, compare a machine pullover to a dumbbell pullover (both single-jointed rotary movements). The dumbbell pullover requires more stabilization and coordination during execution but it doesn’t provide direct resistance (resistance that directly opposes the muscle effort) through a full ROM. Free weights provide single direction resistance.

Single direction resistance doesn’t change its pattern. So as the dumbbell reaches chest height, there isn’t significant resistance directly opposing the shoulder extensors (e.g.- latissimus dorsi). At this point, gravity is pulling the dumbbell towards the floor. If there was rotational resistance, in this same position, the weight would be pulling back overhead, directly opposing the shoulder extensors. The machine pullover provides direct resistance throughout the entire ROM.

Certain body movements are also best accommodated with machines (or manual resistance). Movements such as hip flexion, hip adduction & abduction, and shoulder adduction are more easily and effectively strengthened with selectorized machines.

Most selectorized machines offer some variable resistance. Variable resistance means the resistance employed varies through a given ROM. The cable attached to the weight stack rotates around a cam and the cam’s diameter lessens when the working muscle(s) is naturally weaker and increases when it’s naturally stronger. The resistance mimics the natural force curve of the working muscle(s). While this system is not perfect, some accommodation is better than none.

The emphasis or isolation of specific body parts is another unique characteristic machines offer. While free weights are beneficial for using more muscles than a given machine equivalent, it’s also beneficial at times to reduce or eliminate stabilizing and fixating muscles and force the target muscle(s) to perform virtually allof the work. Any muscle that acts as a stabilizer during a given exercise functions as a prime mover during another. Muscles used for stabilization do not get loaded sufficiently for significant gains in muscle hypertrophy and strength. Machines provide stabilization of the body allowing for muscle isolation.

Machines allow for a more time efficient workout. An individual can move through a resistance circuit a lot faster using selectorized machines. Simply moving a pin in the weight stack and an adjustment on the seat or axis arm takes less time than loading weights and adding locks on a barbell or stacking and changing dumbbells. An issue such as this can sometimes make the difference between exercising or not exercising.

The elderly and physical therapy patients during certain phases of their rehabilitation may benefit more from machines. The added safety, ease of use, and ROM limiters that many machines offer can accommodate these populations best.

Conclusion

Remember that free weights and machines are tools used to meet an individual’s fitness goal. Each RT program must be individualized to meet a specific training goal. What’s more important than selection is how these tools are used (e.g.- technique, intensity, progression). Both free weights and selectorized machines have unique characteristics that make it nearly impossible to truly compare them to each other. As a lifter uses both types of equipment, he \ she may find their body responding better with one or the other. However, both will likely still have a place in their long-term RT program (e.g. - to help break a plateau, avoid repetitive movements, prevent boredom). Table three summarizes free weight and machine applications.

TABLE 3 General Recommendations for Free Weight & Selectorized Machine Use

• Novice exercisers should use machines and free weights.
• Intermediate exercisers should use machines and free weights.
• Advanced exercisers should emphasize free weight use, using machines to complement their program.

Source: Sorace, Paul. Free Weights and Machines. ACSM Certified News. Volume 15; Issue 2. April/May/June 2005.

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