Final answer:
The contraction phase involves the binding of calcium ions to troponin, not the actions of Ca2+ pumps on the SR; these pumps are instead active during the relaxation phase.
Step-by-step explanation:
The statement "The Contraction Phase of a single muscle twitch is specifically due to the actions of the Ca2+ pumps on the sarcoplasmic reticulum (SR)" is False. During the contraction phase of a muscle twitch, the presence of calcium ions (Ca++) in the sarcoplasm is crucial as they bind to troponin, causing tropomyosin to move away from actin-binding sites, forming cross-bridges between actin and myosin filaments and leading to the shortening of sarcomeres. On the other hand, the Ca++ pumps on the SR are primarily involved during the relaxation phase, where they actively transport Ca++ ions from the sarcoplasm back into the SR, helping the muscle fiber to return to its resting state.