Active and Neutral Levers
Seducing Gravity
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Every movement has a moment where the mechanics are working for you and a moment where they aren't. A moment where you are strong and where you are exposed. Knowing which levers are active and which are neutral tells you where that line is. On the right side of the line lies strength, speed, power, glory, and sexual prowess. On the other side—or what the Italians call the sinister side—lies weakness, injury, and ignominy. And most importantly, lost time.
The Rule
Identifying whether a lever is active or neutral comes down to a single relationship:
A fully active lever is perpendicular to the direction of resistance.
A fully neutral lever is parallel to the direction of resistance.
Because movement is dynamic, levers travel through a continuous arc between these two states. As such, the useful question isn't "is this lever active or neutral?" It's "is this lever more active or more neutral than the alternatives?"
The Biceps Curl
At the starting position of a dumbbell biceps curl—arm fully extended at the side—the forearm is perpendicular with the ground and parallel to the direction of resistance, in this case gravity. In this position the forearm is a neutral lever.
The biceps are loaded, but the mechanical challenge to the muscles is near zero, just enough to keep your forearm attached to your humerus.
As the curl begins, the forearm rotates from the elbow toward perpendicular with gravity, and parallel to the ground. The lever becomes progressively more active as it travels.
At 90 degrees of elbow flexion, the forearm is fully perpendicular to gravity—this is the peak active position, where the mechanical demand on the biceps is highest.
Continue past 90 degrees, and the forearm begins traveling toward parallel again. The lever becomes less active and more neutral as it moves toward 180 degrees. Because the elbow cannot physically reach 180 degrees of flexion (since the upper arm is in the way) the movement finishes in a position that is mostly neutral—active enough to maintain tension, but no longer at peak demand.
Another way of phrasing this is the movement starts easy, becomes more difficult, reaches max difficulty at 90 degrees, and then gets easier as it moves toward 180 degrees. We'll look deeper into this when we talk about the resistance curve.
There are two other levers worth noting in the biceps curl: the hand and the upper arm. The hand functions as an extension of the forearm and tracks its active-to-neutral status throughout the movement. The upper arm remains parallel to gravity for the entire curl, making it a neutral lever from start to finish.
The Tennis Serve
The serve is a mechanically demanding movement where suboptimal lever position at the wrong moment results in significant loss of power. Ignoring the rest of the body, let's just look at what the arm and shoulder are doing.
At the trophy position—the loaded backswing before the upward drive begins—the racket arm is deeply flexed at the elbow. Relative to the direction of resistance (gravity), the forearm is angled more perpendicular, making it the active lever. As the arm extends upward toward contact, the forearm travels through its most active position, generating speed through the kinetic chain before the wrist snaps through.
Ideally contact with the ball happens at the moment of full elbow extension where the forearm is approaching neutral. The lever has done its work.
When players lose pace on their serve the issue is typically timing. The arm is reaching full extension too early, too late, or not at all. The lever has failed to deliver the proper amount of force when the racket meets the ball.
Alpine Skiing
Let's examine how the active-to-neutral relationship plays out across two lever systems simultaneously—the pole plant in the upper body and the leg through the turn.
I'd like to avoid getting too complex, but for this example we should clarify what the resistance actually is and where it is coming from, since our lever's status as active or neutral depends on its relationship to the direction of resistance.
Downhill skiing is essentially a controlled fall down a slope. Unlike a biceps curl where we're resisting gravity, the entire point of downhill skiing is to yield to gravity—but on terms of our choosing. To accomplish this we use our levers to transmit force into the slope and then redirect the equal and opposite ground reaction force into making spectacular turns while also avoiding death and dismemberment. Which is another way of saying that the direction of resistance is perpendicular to the angle of the slope.
When a skier initiates a turn, the pole plant is the trigger. For this lever system the direction of resistance runs directly lengthwise through the ski pole itself. Force is transmitted from the skier down through the pole, and the ground reaction force responds with equal and opposite resistance. Since the forearm is more or less perpendicular to the pole for the entire movement, we can consider the forearm the active lever.
The arm drives the pole tip forward and down into the snow with the elbow flexed, creating a fixed point that stabilizes the skier while the lower body rotates into the new turn. The pole plant is effective precisely because the forearm is active at the moment of contact. A straight arm—a neutral lever—produces a weak, late plant that costs the skier the timing window entirely.
As the pole clears and the turn develops, we shift our attention to the leg. At the top of the arc, the outside leg is relatively extended, the shin pressing into the tongue of the boot. The leg is close to vertical—aligned with gravity rather than angled against the direction of loading—a more neutral position that maintains contact and control through the transition.
As the skier moves into the bottom of the turn, the outside leg loads progressively into hip and knee flexion. The ankle moves more into dorsiflexion (toes get closer to the shin). The leg is now driving force through the ski edge at a more active lever position—angled relative to the direction of resistance, which at this point is the combination of gravity and centrifugal force pushing outward through the turn. This is where edge pressure peaks and where the ski generates its maximum grip on the snow.
Coming out of the arc and transitioning to the next turn, the leg extends again, returning toward neutral as the edge releases. The cycle resets with the next pole plant.
The sequence matters as much as any individual position. A pole plant that's late or mechanically weak—neutral when it should be active—disrupts the timing of the leg's loading cycle. The skier can still complete the turn, but they're skiing more on gravity's terms than their own. At race pace, it shows up in the split times.
