* His back is only flesh and blood. Why doesn't lifting huge weights injure it?
** Most likely his entire skeleton (except his head and his left arm) was reinforced, otherwise his legs would also injure him when running.
** This troper has heard, second-hand, that one episode mentioned reinforcements that got implanted in his back for exactly this purpose.
*** The made for TV movie made much later than the series does mention this reinforcement.
* So exactly how did the Venus probe manage to not explode during the long trip from Venus to Earth through the vacuum of space, when it couldn't even handle being lifted a few hundred feet up from the Earth's surface before exploding?
** Fatigue stress from all the forces the probe was subjected from launch, including the Venus flyby and re-entry into Earth's atmosphere? Eventually every material will fail given enough stress applied to it.