Purpose: The purpose of the present study was to examine the impact of 8 days of immobilization during a Special Support and Reconnaissance mission (SSR) on muscle mass, contraction dynamics, maximum jump height/power, and body composition. Methods: Unilateral maximal voluntary contraction, rate of force development, and maximal jump height were tested to assess muscle strength/power along with whole-body impedance analysis before and after SSR. Results: Body weight, fat-free mass, and total body water decreased (4-5%) after SSR, along with impairments in maximal jump height (-8%) and knee extensor maximal voluntary contraction ( -10%). Furthermore, rate of force development was severely affected ( -15-30%). Conclusions: Eight days of immobilization during a covert SSR mission by Special Forces soldiers led to substantial decrements in maximal muscle force and especially in rapid muscle force capacity. This may negatively influence the ability for rapid exfiltration and redeployment, respectively.