Everyone knows that to improve performance, you have to use free weights! Right? Are you sure? The latest research might suggest otherwise. Let’s dive in and see what’s going on and what you need to do as a coach or athlete to improve your sport, work, or life performance.
In this study (Hernández-Belmonte et al., 2023), 34 subjects with training experience were divided into a free-weight and machine group. Both groups were tested on a 20-meter sprint, vertical jump, a zig-zag change of direction drill, the arm and leg Wingate tests (for anaerobic capacity and power), balance, 1RM (for all the free weight and machine exercises used by either group in the training program) and lifting velocity.
After a 2-week familiarization period to get instruction and practice the movements, each group trained 3 times per week for 8 weeks. The free weight group did squats, bench press, prone bench pull (straight bar), and shoulder press. The machine group did machine squats, machine bench press, machine prone bench pull (I assume this is a machine row), and machine shoulder press. Each exercise was done with 65-85 % 1RM load (loads progressed linearly throughout the program), for 3 sets per exercise with 4 minutes rest between sets.
Both groups go stronger. However, the free-weight group gained slightly more strength than the machine-based group in every exercise except for the prone bench pull (the machine group got 0.2% stronger). Both groups improved their speed and vertical jump, but again the free-weight group did slightly better. The free weight group had greater improvement in change of direction performance. While both groups improved anaerobic capacity, again the free weight group had greater improvement. The machine-based group had better improvement in upper and lower limb anaerobic power. Balance improvements were greater in the free-weight group. The machine group had slightly greater gains in quad muscle size.
While it would be nice to see more than 34 subjects, training studies are expensive and hard to do.
It was great to see that the subjects had at least some training experience (i.e., not the complete beginners often used in research).
I like the choice researchers’ choice of assessments. This gives you quite a comprehensive view of athletic performance.
It would have been nice to have a control group that was given the 2-week instruction and practice time, but then didn’t train for the 8 weeks and was then re-tested. This would let us know how effective each program was compared to no training at all.
I didn’t like that there was only one leg exercise used for each group. This program really needed a hip hinge. This is an important exercise that is very difficult to replicate with a machine. If for example, the free-weight group had a Romanian deadlift and then the machine-based group had some hip extension machine, we might have seen a greater difference in performance.
I recognize the challenges with training studies and hugely respect and appreciate every researcher who does a training study. However, 8 weeks is not a lot of time. Hard to draw long-term conclusions. Would free weights have shown more superiority if given a longer period of time? Would free weights help with long-term resilience against injury?
The title and abstract conclusions of this study can be slightly misleading. While there may not be “meaningful” or “statistically significant” differences between the groups, when you look at the numbers the free-weight group did a little better in most of the tests. Remember in the world of athletics, you are looking for every possible spec of improvement.
Application - You and Your Performance
Make sure results, not philosophy drives your training/coaching decisions. Many “functional training” gurus start with their philosophy: machines ≠ function. Then they base their training on this philosophy. Instead, you want to look at results. If using a machine helps you see measurable performance improvements in relevant performance tests – that is great!
See machines as tools in your coaching/training toolbox to use when helpful. For example, the late Charles Poliquin, arguably the most successful strength coach of all time used leg curls in his athlete training programs. I would argue that a glute ham raise, Nordic leg curl, or standing cable leg curl would be better options because they use the glutes with the hamstrings (glutes and hamstrings work together in real life). However, the leg curls worked for Poliquin’s athletes because hamstring strength is important. He also found the seated calf raise (normally considered a bodybuilding exercise) to be excellent for improving ankle dorsi flexion range of motion. Good ankle mobility is important for proper squatting and optimal knee health.
Don’t think you can just play on your favorite machines in the gym and improve your athletic performance. Do not expect to see your performance improve from machine pec flies, leg extensions, and machine curls.
Whether you are using free weights or machines, you need to get substantially stronger on the big movements (i.e., squatting, hinging, pushing, and pulling) to improve your performance.
In this study, they used a machine squat. I don’t think you would see the leg press transferring to improved performance as well as a machine squat. Improving performance is not just about the muscles, it is also about your nervous system. Squats are a closed-chain movement. This means that when you push on the immovable ground, your body moves (like it does in real life). Leg presses are an open-chain exercise. To leg press, you push on the moveable foot pad and it moves while you stay still. In a machine squat, you still work your lower back as a spine stabilizer while your legs are moving. In a leg press, the backrest does the stabilizing for you. Squats also train you in an upright position. With a leg press, are also in a bent-over position that is not useful for most sports. Research shows that while the leg press can help improve vertical jumps, squats work better (Rossi et al., 2018, Wirth et al., 2016).If you need to gain muscle, a machine squat might be a good option for quad mass – especially if you do not have a great structure for the barbell back squat (i.e., short torso, long legs – like many athletes). Other great options include Hip Belt Squats, Safety Squat Bar holding the rack (a.k.a. Hatfield Squat), Zercher Squats (great for long legs and short torsos - also excellent because you can fully extend your hips at the top), Bulgarian Split Squats, and Front Squats.
When training for performance, you have to consider training economy. Yes, physical performance abilities are important, but athletic success in many sports is still mostly about skill and the mental side of things. As a result, training needs to be short as reasonably possible. Big movements allow you to do this. Being wise with your exercise selection allows more time to work on tactics and skills. Free weight movements are superior to isolation machines. Think of how many machine isolation exercises you would have to do to work all the muscles used in a squat or deadlift.
If you are stuck training at some yuppy gym that doesn’t have barbells and a squat rack, all hope is not lost. Do the best you can with what you have. Go to the gym and progressively add weight to your exercises. Spend time working on landing, jumping, sprinting, change of direction work, and conditioning. Practice your sport. You will improve your performance.
Just because you can use something to improve performance, doesn’t mean it is the best. Athletes are always looking for that edge. If you have the choice, make free weight exercises the bulk of your training routine.
Hernández-Belmonte, A., Buendía-Romero, Á., Franco-López, F., Martínez-Cava, A., & Pallarés, J. G. (2023). Adaptations in athletic performance and muscle architecture are not meaningfully conditioned by training free-weight versus machine-based exercises: Challenging a traditional assumption using the velocity-based method. Scandinavian journal of medicine & science in sports, 10.1111/sms.14433. Advance online publication. https://doi.org/10.1111/sms.14433
Rossi, F. E., Schoenfeld, B. J., Ocetnik, S., Young, J., Vigotsky, A., Contreras, B., Krieger, J. W., Miller, M. G., & Cholewa, J. (2018). Strength, body composition, and functional outcomes in the squat versus leg press exercises. The Journal of sports medicine and physical fitness, 58(3), 263–270. https://doi.org/10.23736/S0022-4707.16.06698-6
Wirth, K., Hartmann, H., Sander, A., Mickel, C., Szilvas, E., & Keiner, M. (2016). The Impact of Back Squat and Leg-Press Exercises on Maximal Strength and Speed-Strength Parameters. Journal of strength and conditioning research, 30(5), 1205–1212. https://doi.org/10.1519/JSC.000000000000122