Concentric

Definition

The concentric phase is the portion of an exercise where the working muscle shortens under load to produce force. It is the "lifting" or "pushing" phase - the upward portion of a squat, the pull phase of a row, or the press phase of a wall ball throw. During concentric contraction, muscle fibers generate enough force to overcome the external resistance, producing visible joint movement in the direction of the muscle's action.

How It Works

During concentric contraction, the brain sends a signal through motor neurons to muscle fibers, causing actin and myosin filaments within the sarcomere to slide together, shortening the muscle. This shortening produces force that moves the load against gravity or resistance.

Concentric contractions require more energy (ATP) per unit of force than eccentric contractions because the muscle must actively generate force rather than control a descending load. However, concentric contractions produce less muscle damage than eccentric contractions, resulting in less delayed-onset muscle soreness (DOMS). This has practical implications for training: concentric-dominant exercises (sled pushes, rowing) can be trained at high volume with faster recovery compared to eccentric-heavy exercises (running downhill, lowering heavy deadlifts).

Force production during concentric contractions follows the force-velocity relationship: the faster the contraction speed, the less force the muscle can produce. This is why you can squat less weight explosively than you can with a controlled tempo.

Benefits

• Power development: Training the concentric phase explosively (fast, forceful contractions) builds the power output needed for HYROX^® stations like sled push and wall ball throws.
• Sport-specific speed: Faster concentric contractions produce faster rep speed at stations - directly reducing station splits.
• Reduced soreness: Concentric-focused training produces less DOMS, allowing higher training frequency during heavy training blocks.
• Movement initiation: Every HYROX^® station requires initiating movement from a dead stop (first sled push stride, first wall ball rep). Concentric strength determines how efficiently you overcome inertia.

Practical Application

Concentric-emphasis training methods:

• Sled pushes/pulls: Almost purely concentric - no lowering phase. Train high volume with minimal soreness.
• Explosive concentric tempo: Squat with a controlled 2-sec descent, then drive up as fast as possible. Develops rate of force production.
• Paused reps: Pause at the bottom of a squat for 2 seconds to eliminate the stretch-shortening cycle, then drive concentrically from a dead stop. Builds starting strength.
• Concentric-only rowing: Focus on the drive phase power during each stroke - fast, explosive pulls at 80-85% power.

Tempo notation: In a "3-1-1-0" tempo prescription, the third number represents the concentric phase. "1" means a 1-second concentric contraction. "X" means explosive (as fast as possible).

HYROX^® Context

Concentric strength is the primary determinant of station speed in HYROX^®. The sled push is almost entirely concentric - there is no eccentric lowering phase, which is why sled work can be trained at high volumes without excessive muscle damage. Wall ball throws require an explosive concentric press from the squat position. Rowing demands powerful concentric drive from the legs. Training the concentric phase with intent - moving the weight as fast as good form allows - directly translates to faster station times.

Pair concentric-focused work with isometric training (holds, carries) and eccentric training for complete muscular development.

FAQ

Is the concentric phase the hardest part of a lift? In terms of energy demand, yes - the concentric phase requires the most ATP. But the eccentric phase produces more muscle damage. Both phases are important for comprehensive strength development.

Should I focus on concentric speed in training? Yes, especially for HYROX^®. Research shows that intending to move the bar quickly during the concentric phase - even if the weight moves slowly - recruits more motor units and builds more power than lifting slowly. Always control the eccentric, then drive the concentric with intent.

Find exercises with concentric emphasis for HYROX^® station prep at ROXBASE.