Strength training with free weights is more effective and motivating than strength training with machines
Both strength training with machines and strength training with free weights result in an increase in strength, but that increase is significantly greater if you train with free weights. Sports scientists at the University of Stuttgart report this in Experimental Gerontology. In addition, people who train with weights find strength training more fun, useful and motivating.Study

The researchers got 2 groups of 16 experienced recreational strength athletes aged 60-86 each to do strength training twice a week for six months. Every workout was a full body workout, covering 5 major muscle groups with a basic exercise. The subjects did 3 sets of each exercise with a load of 10-12RM.One group trained on machines. Their workouts included the chest press, the leg press, the upper row, biceps cable curls and triceps cable extensions. The subjects in the other group trained with free weights. Their workouts included the squat, the bench press, bent-over rows, curls and the lying triceps press.
After 26 weeks, the subjects who exercised with free weights [FWT] had built up significantly more strength in their legs and triceps than the subjects who exercised with machines [MT].

The fact that the squat is more effective than the leg press will not surprise the readers of this free web magazine. [More] [More]
The subjects who had trained with free weights liked their trainingroutines more than the subjects in the other group. The subjects in the free weights group were also more motivated to keep exercising and had more often noticed that they functioned better in daily life because of the training.
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Exp Gerontol. 2019 Jul 15;122:15-24.