Science of Lifting: Isometrics

TAGS: dynamic tension, 1RM, triphasic training, Cal Dietz, Mel Siff, isometric movements, brandon patterson, max effort

A Primer on Isometric Training for Strength and Power

Isometric lifts—lifts where the muscles contract without causing movement at the involved joints—might be an under-appreciated tool for lifters and athletes. The reason is that isometric lifts have specific effects that are distinct from their dynamic brethren.

Picture the typical barbell curl. It works the arm flexors through a full range of motion, and performing the exercise will improve your strength all along that range of motion. Isometric actions are different. They have a stronger regional impact on your muscles. Let’s say you pick up that same barbell from a rack with your arms already completely flexed and then hold the bar in that position. This would be a common isometric lift. Rather than strengthening the entire motion, you’ll mainly strengthen the top end of the curl. Similarly, if you were to hold the bar mid-way through a rep (around 90- degrees), you’d primarily strengthen the middle portion of the movement.

The takeaway here is that isometrics have the ability to make exercises far more targeted than dynamic work. Jonathan Mike’s recent piece does an excellent job at explaining the research, so I’ll direct you there for technical details.

All activity has an isometric component whether it’s the tensing of the abdomen to remain upright when sitting or standing, the spinal erectors maintaining a neutral spine during a squat, or the hand flexors gripping an apparatus be it a barbell or a pencil. This isn’t a useful delineator for most people, so in a broad sense, isometric training is generally recognized as any activity where a primary movement is trained (or training is attempted) in a mostly static manner. This means lifts that transition from a moving state to an isometric state (and vice versa) are often called ‘isometric.’

The same is true for forced eccentrics where a load is lowered as a result of fatigue as opposed to an intentional eccentric action. I think this is a case where having a broad definition is practical for the average lifter. Most of these techniques require a similar mindset, and almost as common is the need for similar equipment and cuing.

A catch-all definition will also help us avoid a hodge podge of vocabulary that varies from coach to coach. The verbiage is owed to the fact that isometric training has been discovered, forgotten, and ‘rediscovered’ many times by both popular and scientific sources across the globe. In the United States, isometric training is most associated with Charles Atlas’ programs in the 1920s. Atlas claimed that his methods were inspired by watching a lion stretch at the zoo, and his subsequent dynamic tension program (while largely consisting of calisthenics) featured self-resisted, semi-isometric exercises that fall into our simplified definition.

Atlas’ work brings to mind that probably the oldest form of isometric training is the aesthetically guided, maximum, voluntary contraction, more commonly called ‘flexing.’ A good alternative for the title would probably be ancient children who tried (and failed) to push down trees and walls. Perhaps the oldest organized instances of isometric exercise are found in combat training, as static strength is required to wield weapons and defensive devices, and is an international staple of hand-to-hand combat training. Looking at modern times, isometric training in the more technical sense (and with a focus on weights) had a post-Atlas surge of popularity in the 1950s, though its successes were later deemed to be a result of anabolics. Cal Dietz and Ben Peterson’s triphasic training methods are returning attention to the method, which we’ll look at in a moment.

This pattern of discovery and exclusion has led to varied opinions on isometrics. Among the more research-oriented coaches in the athletic pantheon, Zatsiorsky largely discounts isometric training, Siff was intrigued by older research (though I’ll admit some of it hasn’t been properly verified), and Verkhoshansky scattered the technique selectively throughout his programs. The most common recommendation among coaches (I include Siff and Zatsiorsky in this group) is that for strength and power, traditional isometric actions shouldn’t last much longer than five to eight seconds. This is long enough to fully activate the muscle and gain some psychological benefits from the effort but not so long as to create excessive fatigue. Fatigue is important when it comes to loaded isometric lifts. The technique is demanding, especially if it’s performed along with max effort loads or explosive effort.

Increasing athleticism through isometric means usually involves combining racks and barbells. This allows for the most flexibility of use as well as a high degree of safety. Safety is an especially important consideration for isometric exercises built around loaded squats and bench presses. Isometrics at the lifter’s upper one rep max (1RM) range are very fatiguing. Even an experienced lifter who hasn’t used the method in a while can unexpectedly fail an attempt. For this reason, having safety pins set is often a requirement.

The simplest isometric lift is the weighted lockout. Lifters unrack a load heavier than their 1RM and hold it in this extended position for several seconds. Using the deadlift as an example, the tensed grip, abs, spinal erectors, glutes, and traps all act against the weight and receive a training effect. A thoughtfully positioned rack height allows lifters to more easily move the barbell than they would if pulling it from the floor, which in turn allows for a greater load (and therefore a greater stimulus) than a paused lockout deadlift. I use the deadlift as an example because its effect on muscle, in my experience, is greater than in lockout holds of squats or bench presses (though these two lifts can equally boost confidence and acclimate your body to heavier loads).

Because isometric exercises have the most effect at a particular portion of a movement, they’re especially useful for training through sticking points during a lift and improving the transition between the controlled and explosive portion of a movement. Two common sticking points for the raw powerlifter are the bottom of the bench press and the bottom of the squat. Both can be aided with isometric techniques. The simplest method uses these problematic exercises as their own solutions. The lifter pauses at the bottom of the lift, holds the position tightly for five to eight seconds (i.e. without resting the bar on the chest or pins), and then finishes the lift before repeating for several more reps.

For a Westside-style lifter, this method is a natural fit for either the max effort or dynamic effort lift during a given mesocycle (though probably not both maximal and dynamic at the same time). Both require slightly less weight than normally used for a given rep range (and the max effort method would probably benefit more from low reps instead of singles or 1RM attempts) but otherwise require few changes. The max effort version is also excellent for developing the ability to strain through sticking points.

For other athletes, these methods can be used generally to strengthen a muscular region (the pecs and delts for the bench and the glutes, in particular, for the squat). Moving the pause point within the motion can emphasize different muscles and can also serve to strengthen the transition point between a controlled and an explosive motion. The vertical jump is a good example. Pausing points of poor technique can help train a more synchronized explosive movement, provided that there’s enough pure dynamic training going on to keep the basic jump motion rehearsed. Because isometrics can localize effects, they can even be a tool for bodybuilders to target stubborn muscle groups.

An extended variation of isometric pausing can be useful for ingraining thoughtful lifting technique and also for developing stability during a lift. Using the squat as an example, the lifter lowers the bar with four, planned pauses during the descent, with the final being held at parallel. The lifter then returns the bar in a normal concentric motion or even explosively. If you try this, prepare to be humbled by the light weights you’ll start with.

Another isometric technique is attempting to overcome an immovable object. Rather than pausing at a given point, the lifter sets safety pins above the bar so that its progress is halted during the lift. Instead of lowering the weight when it can no longer move, the lifter attempts to break through the pins, resulting in a prolonged isometric contraction. In lifts where a failed effort can trap the lifter or simply make reracking difficult/impossible (the bench press and squat, again, being good examples), a second pair of safety pins is set below the bar. This sandwiches the weight and lets the lifter work without fear of getting pinned or having to dump the bar. The recommendations for this technique are almost the same as for pause-based isometrics. It can fall easily into the maximal effort or the dynamic lift, and it can develop explosive power for the general athlete. Again, it can be applicable for the bodybuilder, too.

I want to close by mentioning triphasic training (TT). As the name indicates, TT focuses on three modalities of strength training by stacking consecutive phases that each emphasize eccentric, isometric, or concentric strength. The primary lifts of the isometric cycle are reminiscent of shock training activities like depth jumps. The athlete intentionally over accelerates the eccentric portion of a lift (e.g. pulls the barbell down during a bench press). However, instead of rapidly rebounding the bar, he locks the weight in with a tight isometric pause of several seconds before explosively completing the lift. Because the lifts can incorporate heavier loads and want to take advantage of the stretch shortening cycle, TT forgoes usual recommendations by having shorter pauses of as little as three seconds. Longer, more familiar pauses are recommended for traditional isometric techniques.

Unlike the earlier techniques described here, triphasic training's isometric cycle is designed to teach athletes to reactively absorb and express force in all planes and capacities rather than do so in a particular portion of a movement or grind through a sticking point as a powerlifter would probably be more interested in. As Peterson notes, “Your muscles could give out at any time,” which again emphasizes the importance of proper safety equipment. No spot team will ever be as effective at stopping a completely blown pause as a set of pins.

This just touches on the wide spectrum of isometric training. While the jury’s still out on the research, I think the consensus of coaches is that this technique is an effective but very specialized tool. If my opinion counts for anything, I include myself in the coaches’ camp, and I’m looking forward to seeing how science catches up to the application of isometric training and how it continues evolving in weight rooms everywhere.

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