Which training method is effective for helping runners learn to relax opposite muscles while the active muscle works?

The correct choice focuses on exercises aimed at improving running form as the most effective method for helping runners learn to relax opposite muscles while the active muscle works. This method emphasizes the coordination of muscle groups, where the goal is to enhance performance through the refinement of biomechanics.

When runners focus on improving their running form, they often learn to engage their primary muscles more efficiently while simultaneously relaxing the opposing muscle groups. For example, as the quadriceps are activated during running, proper form training can help the hamstrings to not over-contract, thereby creating a smoother, more efficient running gait. This coordination is crucial, as it helps prevent injury and promotes endurance through optimal muscle function.

Other training methods, while beneficial for different aspects of running, such as increasing speed or power, do not specifically target the neuromuscular coordination that is essential for relaxing opposite muscle groups during running. Thus, focusing on running form aligns most closely with the goal of teaching runners to effectively manage and balance muscle contractions while running.