Complex sentence: A year later and he finally acquiesced, although was out of shape and lost most of his muscle; weighing over 300 pounds (136 kg) while Johnson was in superb physical condition.
Split into simpler sentences: A year later, he finally acquiesced, although he was out of shape and had lost most of his muscle. He weighed over 300 pounds (136 kg), while Johnson was in superb physical condition.