Academic journal article Physical Educator

Comparison of Strength Gains in Untrained College-Age Females Using Free Weights and FreeMotion Machines

Academic journal article Physical Educator

Comparison of Strength Gains in Untrained College-Age Females Using Free Weights and FreeMotion Machines

Article excerpt

Resistance training is an effective method for various populations to develop muscular strength. Although free weights are considered the preferred mode of strength training, the development of various weight machines has extended the possible application of resistance training (Crone, 2011). In free weight exercise, the load being lifted remains constant throughout the range of motion. However, according to Crone (2011), the configuration of the joint causes the application of force to change at different points in that range of motion. A variety of weight machines have been designed in an attempt to match the resistance to potential force capability at different points in the range of motion to maximize the development of strength (McMaster, Cronin, & McGuigan, 2009).

Free weights are entirely controlled by the lifter and require the lifter to use synergistic muscles to control the weight throughout the range of motion (McCaw & Friday, 1994). To the contrary, weight machines guide the resistance through a specific path, reducing the activation by synergistic muscles (McCaw & Friday, 1994; Schick et al., 2010). A distinct manufacturer of resistance training machine called FreeMotion (FreeMotion Fitness, 2016) eliminates this fixed-path resistance. However, there is limited research on FreeMotion machines (Spennewyn, 2008). Similar to free weights, FreeMotion machines are controlled exclusively by the lifter and are capable of following an unrestricted range of motion. Dumbbell weights, in particular, are highly comparable to FreeMotion machines because, unlike the barbell or a traditional variable resistance training machine, these modes of training allow the lifter to hold the weight in each hand and perform exercises in a unilateral and unrestricted range of motion.

Because of the similarities in load application between dumbells and FreeMotion machines during the lifting range of motion, there is potential for comparable strength improvements throughout an individual's training. However, it is unclear if one mode of training is superior to the other regarding gains in strength (Langford, McCurdy, Ernest, Doscher, & Walters, 2007; Simpson, Rozenek, Garhammer, Lacourse, & Storer, 1997). With the increasing popularity of resistance training exercise, it would be advantageous to compare muscular strength gains among different strength training modes. Therefore, the purpose of this investigation was to examine the effects of different resistance training programs on the strength of untrained college-age females using dumbbell free weights and FreeMotion machines. It was hypothesized there would be no differences in strength gains between females in the two training methods.



Participants were untrained females (no resistance training within past year) between the ages of 18 and 28 years who volunteered to participate in the study. To participate, the women had to be free from any chronic diseases such as coronary heart disease, diabetes, lung disease, or orthopedic problems that could prevent their participation. Pregnant women could not participate in the study. Additionally, the women had to have a BMI of less than 30 kg/m2 to be eligible to participate. Participants consisted of female undergraduate and graduate students recruited from a university in the southeastern United States. The study was approved by the university institutional review board. All participants completed and signed an informed consent agreement form after having the risks and benefits of the study explained to them. Participants also completed and signed a Physical Activity Readiness Questionnaire (PAR-Q; Canadian Society for Exercise Physiology, 2002) and an American College of Sports Medicine (ACSM, 2014) health history form prior to participating in the study.


The research was conducted in the summer and fall of 2015. There were two waves of recruitment. The summer participants were recruited through a flyer that was e-mailed to all university students and faculty and staff members. …

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