Recently, I had a friend ask if super slow resistance training was better for building strength than standard paced resistance training. This is a really good question. It would make sense that if you were lifting super slow, there would be no momentum while you are lifting weights, thus, your muscle would have to work harder and you would build more strength. Unfortunately, the human body is much more complex than that and the answer to how fast I should lift is not that simple.
The basis of fitness from a scientific perspective is the SAID Principle. The acronym stands for Specific Adaptations to Imposed Demands. This means that when we workout, our bodies specifically adapt to what we do and how you worked that muscle. The key word I want to point out in this acronym is SPECIFIC. This means that our body adapts precisely to the demands we put it through. For example, if you want to get good at running, then you should run. The carry over of muscular use from other activities to running does exist but varies depending on how close the motions are to training the muscles used in the same way. For example, riding a bike will not condition the muscle tissue used in running exactly, so, the carry over will be somewhat minimal. We also adapt specifically to the speed of a muscle contraction. If you want to be a great sprinter, you train through sprinting not endurance running. At this point I would imagine you know where I am going with this… If you lift weights super slow in a gym, your muscles will develop strength lifting super slow. Last time I checked, in real life we don’t move super slow. For our gym activity to carry over as closely as possible to how we lift resistance in real life, we need to mimic that pace.
Fast motion lifting does sometimes apply, but, in general, for most general health and fitness needs, explosive training is unnecessary and can be unsafe. If I am training an athlete for a specific sport, I will include explosive type training (ex: football, basketball, sprinting). Through explosive training in the gym, we can actually mimic muscle use very precisely and challenge muscles above and beyond outside forces in real life. For example, I can train a basketball player to jump higher by doing plyometric box jumping with added load of a medicine ball, challenging the muscle further than a standard jump and improving their vertical leap. Though explosive, these movements still should be controlled. Lifting fast and out of control is NEVER a good approach to working out and is a great way to ask for an injury.
As for pace of lifts when doing resistance training (such as weight training) for purposes of benefiting our general fitness for the non-athlete, the best way to effectively work muscle tissue is to lift weights at a moderately slow and controlled pace. Think about how you would pick up a box in your garage. You wouldn’t throw the box up in the air, and, conversely, you wouldn’t take thirty seconds to lift it up. I teach a 2/3 count to my clients. Two seconds on the lifting phase and three seconds on the negative phase (easy). The idea behind the slower negative phase is to force the muscle to still contract against the resistance during the lowering motion. If you just drop the weight down, momentum is doing all the work, not the muscle. The 2/3 count will keep your pacing under control and you will be done with your set before the sun goes down. You also want to include isometric muscle use during your workouts in those muscles that are primarily used in an isometric fashion. These muscle include our core muscles (abs and lower back). Isometric use means that the muscle contracts to hold our posture etc. (no movement). Our abs and low back provide spinal posture support most of the time and contribute through movement (like an ab crunch) infrequently. A good way to tackle this type of use for our core is through timed plank exercises and yoga. Planks require far more strength than merely holding our posture and by asking that demand of those muscles, they will build strength and contribute to joint support of the spine.
The key to great lifelong health and fitness or improving in sport is to train specifically for what you are trying to achieve. Even our speed of motion when working out should reflect that. Make sure your workouts apply to what you do in life. No matter what, never sacrifice control or proper form during your lifting.