Thanks for your query
Bruising may occur due to rupture of capillaries of skin due to any injury
or sometimes spontaneously.
done last year should not have any effect on this.
If the push-ups are causing any trauma to a particular part of skin and bruising is visible there, you will need to be more careful.However, this is not a routine cause.
You can take Oral Vit.C to help in this condition.Doing warm compresses helps in faster resolution of the bruises.
Hope this helps.Take care!