You can try calisthenics exercises improve physique, strengthen the body, boost confidence and enhances the personality. In addition, it reduces stress and relaxes the tension in muscles. It improves sleeping patterns and facilitates sound mental health. The bonus point is that there is a huge range of calisthenics workout for women and men to choose from. Thus, it never gets boring.So you can try them for MMA takedowns.
Weight training to develop the strength needed for takedowns. A suggested rep scheme of a heavy weight for 6-12 reps since any less will spark the growth of fast twitch muscle fibers which will fatigue faster. You are training your client for fighting, not bodybuilding so incorporate the push/pull method because in fighting you strike (push) and grapple (pull).
Personally I feel that although important, weight training isn’t a priority. Muscle mass will make for a stronger athlete but if the athlete lacks technique it won’t matter in the ring. The best exercise routine for MMA takedowns is to do them via partner training.
Similar to stand up, when asked how do you improve your kicks & punches? – you practice kicking and punching!
Also no one mentioned cardio! I mean after all the one who tires first becomes the loser.
Here is an article which you might find interesting on training the MMA athlete using the ACE IFT Model
Since your question is based on takedowns in general and not a specific type of takedown (ie. slam, drag down, push down..), a good routine could follow grip and squeeze pressure (we don’t want them breaking loose in mid takedown) as well as back extention and leg strength. A lot of fighters here practice push/pull methods to deliver more force than can be generated from a stand still. The MOST important factors in takedowns are commitment and follow through so, plyometric exercises could also provide a good basis for muscle memory (you know, like instinct). Good luck!