How to: Get into a high plank position with your shoulders aligned with your hands (a). Engage your abdominal muscles and hold the plank for 10 ...Photo:RyanKelly/DailyBurnPlanks,crunches,Russiantwists—we’renostrangerstotheclassicabexercises.Butifyouwanttodialuptheintensitywithoutsloggingthroughtonsofreps,consideraddingmountainclimberstoyourcoreroutine.Thesesweat-inducingabexercisesdemandstabilityfromtheshouldersandcore,whiledeliveringplyometrictrainingviathequick(butcontrolled)kneedrives.Strengthandcardiovascularenduranceaside,thisbodyweightmovewillalsohelpbuildrangeofmotioninthosepeskytighthips(mobilityFTW).Evenbetter:Takingyourfitnesstogreatheights(withoutactuallygoinganywhere)takesnotimeatall.Justafewsetstackedontoyourusualcircuitsor Tabatasisallyouneedtofeelthefireinyourabs. Refreshyourfallfitnessroutinewiththese fivemountainclimbervariationsfromourfavoriteDailyBurn365trainers.RELATED:AbChallenge:5PlankstoSculptYourCore5MountainClimberstoSculptYourAbsGIF:DailyBurn3651.ArmyCrawlMountainClimbersIfyou’retrainingforanupcomingSpartanrace,mudraceorobstaclecourse,you’llwanttoperfectthismountainclimbervariation.Thegrittymovemimicstheexperienceoftreadingthroughmudandbarbedwire.Engagingyourabdominalsmuscles,obliques,shouldersandarms,thisexercisechallengesyourstability,too.Howto:Getintoaforearmplankpositionwithaneutralspineandhandscurledintofists(a).Bendyourrightkneeandinchyourrightfoottowardyourrightelbow.Atthesametime,maintainingyourforearmplank,bringyourleftarmforward(b).Then,bendyourleftkneeandinchyourleftfoottowardyourleftelbowandbringyourrightarmforward(c).Placeyourleftfootoveryourrightfoottogetintoaforearmsideplankwithyourbodyfacingtheleftside.Engagingyourcoreforbalance,liftyourlefthandtotheskywithyourfingertipsreachingfortheceiling(d).Returntothestartingpositionandbegintheexerciseontheleftsidethistime (e).GIF:DailyBurn2.PlankJackMountainClimbersCombineyourloveforjumpingjacksandplanks(justus?)inthisultimateheart-pumpingcoremove.Thismountainclimbernotonlyteststhelim