How does stress typically affect physical performance?

Stress typically affects physical performance by increasing muscle tension and impairing focus. When a person experiences stress, the body enters a heightened state of alertness, often referred to as the "fight or flight" response. This response leads to the release of stress hormones, such as cortisol and adrenaline, which can result in increased muscle tension. While some level of muscle tension can be beneficial for performance, excessive tension can restrict movement, reduce flexibility, and lead to fatigue.

Additionally, stress can impair cognitive functions such as focus and concentration. When an athlete’s mind is preoccupied with stressors, it can distract from the task at hand, leading to decreased performance and an increased likelihood of errors. This diminished focus can negatively impact timing, coordination, and decision-making during physical activity.

In contrast, the other options presented do not accurately reflect the typical effects of stress on physical performance. Stress does not significantly improve muscle recovery, nor does it generally enhance concentration and endurance. Additionally, while certain stress responses may increase alertness, they do not prevent injuries, which are often a result of impaired focus and increased tension.