Enhancing reactive strength index through braking-phase focused verbal instruction

Area of Science:

• Biomechanics
• Sports Science
• Human Movement

Background:

• The reactive strength index (RSI) is crucial for explosive performance in activities like sprinting.
• Optimizing neuromuscular strategies during plyometrics can enhance athletic capabilities.
• The impact of specific verbal cues on acute RSI enhancement is not well-understood.

Purpose of the Study:

• To investigate if verbal instruction emphasizing force exertion during the braking phase of rebound jumps can acutely improve RSI.
• To determine if this instruction influences soleus muscle preactivation.

Main Methods:

• Seventeen physically active men without prior plyometric experience were recruited.
• Participants were randomly assigned to an intervention group (standard + braking-phase instruction) or a control group (standard instruction only).
• Both groups performed repeated rebound jumps, with RSI and soleus preactivation measured.

Main Results:

• The intervention group showed a significant increase in RSI (p < 0.05).
• Greater soleus muscle preactivation was observed in the intervention group before ground contact.
• No significant changes in RSI were found in the control group.

Conclusions:

• Targeted verbal instruction focusing on the braking phase can acutely enhance RSI in untrained individuals.
• This simple intervention appears to optimize neuromuscular strategies for improved plyometric performance.
• Coaches can utilize such verbal cues as a practical tool to boost explosive power.