Day #,Work Out
Title,90DayChallenges.com | Core Workout Challenge
How it works,3 phases (Foundation → Strength → Power)
How it works,"• 5 days on / 2 days off each week
• Each workout takes 10–20 minutes
• Increase reps or difficulty each phase"
Day 1,"• Plank — 3×20–30 sec
• Dead Bug — 3×10 each side
• Glute Bridge — 3×15
• Crunches — 3×15
• Reverse Crunches — 3×10"
Day 2,"• Side Plank — 3×20 sec each side
• Bird-Dog — 3×12 each side
• Mountain Climbers — 3×30 sec
• Toe Taps — 3×12 each side"
Day 3,"• Plank — 3×20–30 sec
• Dead Bug — 3×10 each side
• Glute Bridge — 3×15
• Crunches — 3×15
• Reverse Crunches — 3×10"
Day 4,"• Side Plank — 3×20 sec each side
• Bird-Dog — 3×12 each side
• Mountain Climbers — 3×30 sec
• Toe Taps — 3×12 each side"
Day 5,"• Plank — 3×20–30 sec
• Dead Bug — 3×10 each side
• Glute Bridge — 3×15
• Crunches — 3×15
• Reverse Crunches — 3×10"
Day 6,REST
Day 7,REST
Day 8,"• Plank — 3×20–30 sec
• Dead Bug — 3×10 each side
• Glute Bridge — 3×15
• Crunches — 3×15
• Reverse Crunches — 3×10"
Day 9,"• Side Plank — 3×20 sec each side
• Bird-Dog — 3×12 each side
• Mountain Climbers — 3×30 sec
• Toe Taps — 3×12 each side"
Day 10,"• Plank — 3×20–30 sec
• Dead Bug — 3×10 each side
• Glute Bridge — 3×15
• Crunches — 3×15
• Reverse Crunches — 3×10"
Day 11,"• Side Plank — 3×20 sec each side
• Bird-Dog — 3×12 each side
• Mountain Climbers — 3×30 sec
• Toe Taps — 3×12 each side"
Day 12,"• Plank — 3×20–30 sec
• Dead Bug — 3×10 each side
• Glute Bridge — 3×15
• Crunches — 3×15
• Reverse Crunches — 3×10"
Day 13,REST
Day 14,REST
Day 15,"• Plank — 3×20–30 sec
• Dead Bug — 3×10 each side
• Glute Bridge — 3×15
• Crunches — 3×15
• Reverse Crunches — 3×10"
Day 16,"• Side Plank — 3×20 sec each side
• Bird-Dog — 3×12 each side
• Mountain Climbers — 3×30 sec
• Toe Taps — 3×12 each side"
Day 17,"• Plank — 3×20–30 sec
• Dead Bug — 3×10 each side
• Glute Bridge — 3×15
• Crunches — 3×15
• Reverse Crunches — 3×10"
Day 18,"• Side Plank — 3×20 sec each side
• Bird-Dog — 3×12 each side
• Mountain Climbers — 3×30 sec
• Toe Taps — 3×12 each side"
Day 19,"• Plank — 3×20–30 sec
• Dead Bug — 3×10 each side
• Glute Bridge — 3×15
• Crunches — 3×15
• Reverse Crunches — 3×10"
Day 20,REST
Day 21,REST
Day 22,"• Plank — 3×20–30 sec
• Dead Bug — 3×10 each side
• Glute Bridge — 3×15
• Crunches — 3×15
• Reverse Crunches — 3×10"
Day 23,"• Side Plank — 3×20 sec each side
• Bird-Dog — 3×12 each side
• Mountain Climbers — 3×30 sec
• Toe Taps — 3×12 each side"
Day 24,"• Plank — 3×20–30 sec
• Dead Bug — 3×10 each side
• Glute Bridge — 3×15
• Crunches — 3×15
• Reverse Crunches — 3×10"
Day 25,"• Side Plank — 3×20 sec each side
• Bird-Dog — 3×12 each side
• Mountain Climbers — 3×30 sec
• Toe Taps — 3×12 each side"
Day 26,"• Plank — 3×20–30 sec
• Dead Bug — 3×10 each side
• Glute Bridge — 3×15
• Crunches — 3×15
• Reverse Crunches — 3×10"
Day 27,REST
Day 28,REST
Day 29,"• Plank — 3×20–30 sec
• Dead Bug — 3×10 each side
• Glute Bridge — 3×15
• Crunches — 3×15
• Reverse Crunches — 3×10"
Day 30,"• Side Plank — 3×20 sec each side
• Bird-Dog — 3×12 each side
• Mountain Climbers — 3×30 sec
• Toe Taps — 3×12 each side"
Day 31,"• Plank — 3×45–60 sec
• Hanging Knee Raises (or lying leg raises) — 3×12
• Weighted or Slow Crunches — 3×20
• Bicycle Crunches — 3×20
• Heel Touches — 3×25"
Day 32,"• Side Plank Hip Dips — 3×12 each side
• Russian Twists — 3×20 each side
• Flutter Kicks — 3×30 sec
• V-Ups — 3×12
• High Knees — 3×45 sec"
Day 33,"• Plank — 3×45–60 sec
• Hanging Knee Raises (or lying leg raises) — 3×12
• Weighted or Slow Crunches — 3×20
• Bicycle Crunches — 3×20
• Heel Touches — 3×25"
Day 34,REST
Day 35,REST
Day 36,"• Plank — 3×45–60 sec
• Hanging Knee Raises (or lying leg raises) — 3×12
• Weighted or Slow Crunches — 3×20
• Bicycle Crunches — 3×20
• Heel Touches — 3×25"
Day 37,"• Side Plank Hip Dips — 3×12 each side
• Russian Twists — 3×20 each side
• Flutter Kicks — 3×30 sec
• V-Ups — 3×12
• High Knees — 3×45 sec"
Day 38,"• Plank — 3×45–60 sec
• Hanging Knee Raises (or lying leg raises) — 3×12
• Weighted or Slow Crunches — 3×20
• Bicycle Crunches — 3×20
• Heel Touches — 3×25"
Day 39,"• Side Plank Hip Dips — 3×12 each side
• Russian Twists — 3×20 each side
• Flutter Kicks — 3×30 sec
• V-Ups — 3×12
• High Knees — 3×45 sec"
Day 40,"• Plank — 3×45–60 sec
• Hanging Knee Raises (or lying leg raises) — 3×12
• Weighted or Slow Crunches — 3×20
• Bicycle Crunches — 3×20
• Heel Touches — 3×25"
Day 41,REST
Day 42,REST
Day 43,"• Plank — 3×45–60 sec
• Hanging Knee Raises (or lying leg raises) — 3×12
• Weighted or Slow Crunches — 3×20
• Bicycle Crunches — 3×20
• Heel Touches — 3×25"
Day 44,"• Side Plank Hip Dips — 3×12 each side
• Russian Twists — 3×20 each side
• Flutter Kicks — 3×30 sec
• V-Ups — 3×12
• High Knees — 3×45 sec"
Day 45,"• Plank — 3×45–60 sec
• Hanging Knee Raises (or lying leg raises) — 3×12
• Weighted or Slow Crunches — 3×20
• Bicycle Crunches — 3×20
• Heel Touches — 3×25"
Day 46,"• Side Plank Hip Dips — 3×12 each side
• Russian Twists — 3×20 each side
• Flutter Kicks — 3×30 sec
• V-Ups — 3×12
• High Knees — 3×45 sec"
Day 47,"• Plank — 3×45–60 sec
• Hanging Knee Raises (or lying leg raises) — 3×12
• Weighted or Slow Crunches — 3×20
• Bicycle Crunches — 3×20
• Heel Touches — 3×25"
Day 48,REST
Day 49,REST
Day 50,"• Plank — 3×45–60 sec
• Hanging Knee Raises (or lying leg raises) — 3×12
• Weighted or Slow Crunches — 3×20
• Bicycle Crunches — 3×20
• Heel Touches — 3×25"
Day 51,"• Side Plank Hip Dips — 3×12 each side
• Russian Twists — 3×20 each side
• Flutter Kicks — 3×30 sec
• V-Ups — 3×12
• High Knees — 3×45 sec"
Day 52,"• Plank — 3×45–60 sec
• Hanging Knee Raises (or lying leg raises) — 3×12
• Weighted or Slow Crunches — 3×20
• Bicycle Crunches — 3×20
• Heel Touches — 3×25"
Day 53,"• Side Plank Hip Dips — 3×12 each side
• Russian Twists — 3×20 each side
• Flutter Kicks — 3×30 sec
• V-Ups — 3×12
• High Knees — 3×45 sec"
Day 54,"• Plank — 3×45–60 sec
• Hanging Knee Raises (or lying leg raises) — 3×12
• Weighted or Slow Crunches — 3×20
• Bicycle Crunches — 3×20
• Heel Touches — 3×25"
Day 55,REST
Day 56,REST
Day 57,"• Plank — 3×45–60 sec
• Hanging Knee Raises (or lying leg raises) — 3×12
• Weighted or Slow Crunches — 3×20
• Bicycle Crunches — 3×20
• Heel Touches — 3×25"
Day 58,"• Side Plank Hip Dips — 3×12 each side
• Russian Twists — 3×20 each side
• Flutter Kicks — 3×30 sec
• V-Ups — 3×12
• High Knees — 3×45 sec"
Day 59,"• Plank — 3×45–60 sec
• Hanging Knee Raises (or lying leg raises) — 3×12
• Weighted or Slow Crunches — 3×20
• Bicycle Crunches — 3×20
• Heel Touches — 3×25"
Day 60,"• Side Plank Hip Dips — 3×12 each side
• Russian Twists — 3×20 each side
• Flutter Kicks — 3×30 sec
• V-Ups — 3×12
• High Knees — 3×45 sec"
Day 61,"• Plank — 3×75–90 sec
• Leg Raises — 3×15
• Jackknife Sit-Ups — 3×15
• Plank to Push-Up — 3×12
• Jump Tucks — 3×20"
Day 62,REST
Day 63,REST
Day 64,"• Plank — 3×75–90 sec
• Leg Raises — 3×15
• Jackknife Sit-Ups — 3×15
• Plank to Push-Up — 3×12
• Jump Tucks — 3×20"
Day 65,"Circuit — 3 rounds:
• 30 sec bicycle crunches
• 30 sec mountain climbers
• 30 sec sit-ups
• 30 sec plank
• 30 sec rest"
Day 66,"• Plank — 3×75–90 sec
• Leg Raises — 3×15
• Jackknife Sit-Ups — 3×15
• Plank to Push-Up — 3×12
• Jump Tucks — 3×20"
Day 67,"Circuit — 3 rounds:
• 30 sec bicycle crunches
• 30 sec mountain climbers
• 30 sec sit-ups
• 30 sec plank
• 30 sec rest"
Day 68,"• Plank — 3×75–90 sec
• Leg Raises — 3×15
• Jackknife Sit-Ups — 3×15
• Plank to Push-Up — 3×12
• Jump Tucks — 3×20"
Day 69,REST
Day 70,REST
Day 71,"• Plank — 3×75–90 sec
• Leg Raises — 3×15
• Jackknife Sit-Ups — 3×15
• Plank to Push-Up — 3×12
• Jump Tucks — 3×20"
Day 72,"Circuit — 3 rounds:
• 30 sec bicycle crunches
• 30 sec mountain climbers
• 30 sec sit-ups
• 30 sec plank
• 30 sec rest"
Day 73,"• Plank — 3×75–90 sec
• Leg Raises — 3×15
• Jackknife Sit-Ups — 3×15
• Plank to Push-Up — 3×12
• Jump Tucks — 3×20"
Day 74,"Circuit — 3 rounds:
• 30 sec bicycle crunches
• 30 sec mountain climbers
• 30 sec sit-ups
• 30 sec plank
• 30 sec rest"
Day 75,"• Plank — 3×75–90 sec
• Leg Raises — 3×15
• Jackknife Sit-Ups — 3×15
• Plank to Push-Up — 3×12
• Jump Tucks — 3×20"
Day 76,REST
Day 77,REST
Day 78,"• Plank — 3×75–90 sec
• Leg Raises — 3×15
• Jackknife Sit-Ups — 3×15
• Plank to Push-Up — 3×12
• Jump Tucks — 3×20"
Day 79,"Circuit — 3 rounds:
• 30 sec bicycle crunches
• 30 sec mountain climbers
• 30 sec sit-ups
• 30 sec plank
• 30 sec rest"
Day 80,"• Plank — 3×75–90 sec
• Leg Raises — 3×15
• Jackknife Sit-Ups — 3×15
• Plank to Push-Up — 3×12
• Jump Tucks — 3×20"
Day 81,"Circuit — 3 rounds:
• 30 sec bicycle crunches
• 30 sec mountain climbers
• 30 sec sit-ups
• 30 sec plank
• 30 sec rest"
Day 82,"• Plank — 3×75–90 sec
• Leg Raises — 3×15
• Jackknife Sit-Ups — 3×15
• Plank to Push-Up — 3×12
• Jump Tucks — 3×20"
Day 83,REST
Day 84,REST
Day 85,"• Plank — 3×75–90 sec
• Leg Raises — 3×15
• Jackknife Sit-Ups — 3×15
• Plank to Push-Up — 3×12
• Jump Tucks — 3×20"
Day 86,"Circuit — 3 rounds:
• 30 sec bicycle crunches
• 30 sec mountain climbers
• 30 sec sit-ups
• 30 sec plank
• 30 sec rest"
Day 87,"• Plank — 3×75–90 sec
• Leg Raises — 3×15
• Jackknife Sit-Ups — 3×15
• Plank to Push-Up — 3×12
• Jump Tucks — 3×20"
Day 88,"Circuit — 3 rounds:
• 30 sec bicycle crunches
• 30 sec mountain climbers
• 30 sec sit-ups
• 30 sec plank
• 30 sec rest"
Day 89,"• Plank — 3×75–90 sec
• Leg Raises — 3×15
• Jackknife Sit-Ups — 3×15
• Plank to Push-Up — 3×12
• Jump Tucks — 3×20"
Day 90,REST