No. 4 [Knockout Power]

Fighting on any level is extremely demanding. It requires stamina, precision, strength, and power. 

Vitality athlete Tabatha Ricci won her fight against Amanda Ribas via second-round TKO at UFC Abu Dhabi on July 26, 2025. Ricci's victory was a significant one, marking one of the biggest wins of her career.

Knockouts require extreme amounts of power. But power is more than strength. There is an element of speed that is required. The faster top-end force can be produced, the more power that is generated. Today, Physiology in the Field takes a closer look at what it takes to generate knockout power through a concept called "Rate of Force Production" or RFD.

The Physiology in Action

The rate of force development (RFD) is a measure of how quickly a person can generate force with their muscles. A high RFD helps with explosive movements, such as sprinting, jumping, and changing direction quickly. Increasing RFD can improve speed and power performance.

The nervous system plays a key role in RFD, as it controls the speed and strength of muscle contractions. Nerves send signals to muscles to contract through the recruitment of motor units, or bundles of muscle fibers that work together to generate force. The more motor units recruited, the more force produced. During explosive movements, nerves quickly send lots of signals that activate numerous motor units at once, increasing the speed and power with which muscles can contract.

The rate of force development is also influenced by muscle fiber type. Muscle fibers can be classified as Type I or Type II. Type I fibers are considered “slow-twitch,” meaning they contract slowly, generate less force, but take longer to tire out. Type II fibers, on the other hand, are considered fast-twitch fibers that contract quickly, generate more force, but tire out more quickly. Individuals with a higher percentage of specific Type II fibers can produce force rapidly, improving speed and power during explosive movements.

The Vitality Plan 

Great achievement doesn’t happen by chance. Finding ways to support the physiology required to realize these feats is paramount. 

Lifestyle: Resistance Training. Training with the intent to move the weight as quickly as possible has been shown to improve RFD (source).

Supplement: Creatine. Supplement with at least 0.066 g of creatine per pound of body weight daily. Creatine has been shown to enhance strength and power (source).

Nutrition: Prioritize protein-rich foods. Eat 0.8 to 1.2 g of protein per pound of body weight per day. Protein supports muscle growth, strength, and power (source). 

Explore the Vitality Encyclopedia to learn more about these topics.