The Overlooked Role of Braking Forces

When an athlete sprints and suddenly decelerates, the body must absorb a large amount of mechanical energy in a short time. These are not mild forces. Braking forces during deceleration can reach 3 to 6 times an athlete’s bodyweight, depending on the entry velocity and surface type.

To put that in perspective: while sprinting might generate ground reaction forces of 2.5–3.5x bodyweight in the vertical direction, braking requires the application of large negative horizontal forces—often measured at -1.5 to -2.5 N/kg of body mass. The athlete must control those forces eccentrically, particularly through the quadriceps, hamstrings, glutes, and ankle stabilizers, while maintaining posture and joint alignment.

Unlike acceleration or top-speed sprinting, deceleration occurs under rapid eccentric loading, meaning the muscle lengthens while under tension. This form of loading places high demands on the musculoskeletal and neuromuscular systems, particularly during sharp changes of direction or high-velocity stops.

At Ground Force, we view deceleration not as an afterthought but as a foundational quality. And we train it where it matters: in the weight room.

High eccentric muscle actions, especially in the hamstrings and quadriceps.

• Large braking impulses over short ground contact times (~100–300 milliseconds).

• Increased anterior tibial shear forces at the knee, which heightens ACL strain.

• Elevated stress on hip and trunk control systems, especially when body angles become compromised under fatigue.

Most hamstring injuries occur during high-speed running, particularly in the late swing phase, where the hamstring must contract eccentrically to decelerate the forward-moving tibia. However, what’s often overlooked is how poor deceleration mechanics and underdeveloped eccentric strength amplify that risk.

In soccer, where repeated sprint-stop efforts are performed hundreds of times per match, the cumulative mechanical load on the hamstrings becomes a significant concern.

When the athlete lacks the eccentric strength to decelerate effectively, the hamstrings compensate by trying to manage forces they are not equipped to handle.

Research supports this:

• van der Horst et al. (2015) identified eccentric hamstring weakness as a key risk factor for hamstring strain injuries in soccer players.

• Opar et al. (2013) emphasized the importance of eccentric strength testing and intervention as a primary preventative approach.

• Athletes with poor deceleration ability also demonstrate asymmetrical loading patterns, which can lead to chronic overload on one limb and compensatory injuries elsewhere in the kinetic chain.

Non-contact ACL injuries are frequently associated with deceleration actions, particularly when:

• Ground contact occurs in a near-extended knee position.

• The trunk angle is upright, shifting load forward.

• There is excessive valgus collapse due to weak glutes and poor limb control.

• The athlete lacks the eccentric quadriceps strength to manage braking loads appropriately.

During sharp deceleration, anterior tibial shear increases dramatically, especially when landing or stopping with limited knee flexion.

Without sufficient eccentric strength in the quadriceps and co-contraction from the hamstrings, the tibia moves forward relative to the femur, placing stress on the ACL.

To prepare athletes to withstand these demands, we structure our weight room sessions around the principle of eccentric overload and braking capacity. We are not just interested in lifting heavy or producing force—we are training athletes to absorb it, control it, and redirect it safely.

Movements such as the rear-foot elevated split squat (tempo-controlled), Romanian deadlift, Nordic hamstring curl, and trap bar deadlift with pauses provide eccentric stress in controlled environments. These lifts mimic the hip, knee, and trunk positions seen during actual deceleration events.

We also target ankle stiffness and joint positioning through accessory movements like tibialis raises, reverse sled drags, and deep isometric wall sits. These smaller pieces play a massive role in how athletes reposition themselves under duress.

When structured with intention, the weight room becomes a tool not just for building force but for reinforcing position, posture, and protection. Deceleration is a skill—one that can be trained and progressively overloaded.

Every time a player stops, cuts, or slows down, they are performing one of the most mechanically demanding tasks in sport. Deceleration is where poor positioning becomes injury, and where lack of strength becomes a compensatory pattern. By training eccentric control and force absorption in the weight room, we give our athletes the physical capacity to brake with confidence.

At Ground Force, we believe that how you stop is just as important as how you start. The Perform First app now includes a training system that integrates deceleration drills, weight room progressions, and tracking metrics to support real-world performance improvements.

If you’re a parent, athlete, or coach interested in improving movement quality while reducing injury risk, our deceleration system is now available for application. Because in the game of soccer, it’s not just about going fast—it’s about stopping strong.

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