Abstract: A muscle toner comprises a cylinder assembly having a closed end with a handle connected thereto. A piston assembly carrying a second handle is slidably mounted in the opposite end of the cylinder assembly. Seals are provided for sealing the interior space of the cylinder assembly. The piston assembly has a piston rod with an active surface area on which an elevated static operating pressure established in the cylinder assembly acts. This pressure tends to push the piston assembly outwardly of the cylinder assembly. The handles can be pushed together against this static pressure to conduct an exercise routine. A normally closed valve pin operated inflating valve is connected in the piston assembly and can be used in conjunction with a valve pin and bicycle pump to inflate the cylinder assembly to a selected static operating pressure.