Most of this category is not fragile. It is awkward, and awkward is a price problem rather than a damage problem.
Check length and weight first
Couriers price on length as well as weight, and long parcels attract surcharges or get refused outright. A cricket bat, a racket bag and a barbell are three different conversations with the same courier.
Find out before you set a delivery price, because the difference comes off your own balance and not the buyer's. How delivery is charged, setting up delivery.
For heavy gym equipment, offer collection and say so in the listing.
Bats
Wrap the blade, pad the toe and the shoulders separately, protect the edges, and use a long box rather than wrapping alone. Keep padding off any signature. Packing cricket memorabilia if it is signed.
Rackets
In their cover, then bubble around the head and the throat, then a box. The frame is strong; the grommets and the string are not.
Shoes
In a box, with the shoe box inside it rather than used as the parcel. Stuff the toes so the shape holds. Packing sneakers.
Weights and metal
Each plate wrapped, then boxed in a box that can actually take the weight — double-walled, taped on every seam, and not too large to lift. A heavy parcel in a weak box fails at the bottom, every time.
Anything with a cable or a bearing
Secure moving parts so they cannot swing. Remove what detaches, wrap it separately, and list it in the parcel so nothing is thrown out with the filling.
Questions people ask
Can I post a bat?
Usually, in a long box, at a price you have checked first. Some services will not take the length.
Do I need to drain or clean equipment?
Clean it, yes. Nobody wants somebody else's season in a parcel.
What if the courier refuses it?
That is the reason to offer collection on long and heavy items from the start, rather than after the sale.