Final answer:
Too much overlap of filaments in a sarcomere causes reduced muscle tension because the optimal filament overlap for cross-bridge formation is exceeded, leading to inefficient muscle contraction.
Step-by-step explanation:
When there is too much overlap of filaments in a sarcomere, the muscle cannot produce maximal tension. The ideal length of a sarcomere for maximal tension production is when thick and thin filaments overlap to the greatest extent without excess shortening. Excess shortening leads to a reduced zone of overlap, whereby thin filaments start to overlap with each other instead of the thick filaments. This results in fewer myosin heads forming cross-bridges with actin, leading to reduced tension in the muscle fiber. On the extreme end, if the sarcomere is overstretched to where there is no filament overlap, no tension can be produced at all due to the absence of cross-bridges.