For Phase 4 of training which focuses on maximal strength, the tempo should be fast and explosive to engage fast-twitch muscle fibers and maximize strength gains, while the eccentric phase should be controlled for safety and proper form.
In the context of maximal strength training (Phase 4), the recommended tempo is typically b) Fast and explosive. The reason for this recommendation is that maximal strength training focuses on lifting a maximal or near-maximal weight for a low number of repetitions.
This type of training usually targets the recruitment of fast-twitch muscle fibers, which are best engaged through quick, explosive movements to generate the maximum amount of force. When performing exercises intended to develop maximal strength, the concentric (lifting) phase is executed rapidly and with full effort, while the eccentric (lowering) phase can be controlled and slower to ensure safety and proper form.
For maximal strength training, the tempo should be fast and explosive during the concentric phase to fully activate the fast-twitch fibers and optimize strength gains. However, a controlled tempo is still important during the eccentric phase to maintain safety and technique.