The Ins and Outs Core Strength Test is part of the Fit Test for the P90X Home Fitness Workout. The test involves sitting on the floor and repeatedly bending and straightening the legs out in front of the body, providing a comprehensive assessment of abdominal and hip flexor endurance.

How to Perform the Ins and Outs Test

Test Purpose: To measure abdominal core muscle strength and endurance, specifically targeting the rectus abdominis and hip flexors.

Equipment Required: None - this is a bodyweight assessment that can be performed anywhere with a flat surface.

Procedure: For an 'in and out' you start seated with your hands on the floor at your sides, knees bent with feet on the floor. Raise your feet off the ground and bring the knees in towards your chest. This is the test start position. Straighten your legs out in front of you, then back in to the chest, without the feet touching the floor. This is one complete repetition. Repeat this movement as many times as possible while maintaining proper form.

Scoring: The maximum number of full repetitions successfully completed is recorded. P90X guidelines suggest that you should be able to do at least 25 repetitions to meet the minimum fitness standard for their program.

Advantages: A simple test to perform on your own with no equipment required. The movement pattern directly correlates with functional core strength needed in many sports and daily activities.

Understanding Your Ins and Outs Test Results

Your score on the Ins and Outs test reflects your core muscular endurance capacity. Unlike maximum strength tests, this assessment measures how many repetitions you can perform before fatigue significantly impacts your form. The rating categories are based on general fitness populations and align with the P90X program standards:

Below Average (<15 reps): Indicates limited core endurance. Focus on foundational core exercises before progressing.

Average (15-24 reps): Basic core strength present. Room for improvement before tackling advanced programs.

Good (25-34 reps): Meets P90X minimum standard. Solid foundation for most fitness activities.

Very Good (35-49 reps): Above-average core endurance. Ready for advanced training programs.

Excellent (50-74 reps): Superior core strength. Typical of dedicated athletes and fitness enthusiasts.

Elite (75+ reps): Exceptional performance. Common among competitive athletes and fitness professionals.

The Science Behind the Ins and Outs Test

The Ins and Outs exercise targets multiple muscle groups simultaneously, making it an effective assessment of integrated core function. The primary muscles engaged include:

  • Rectus Abdominis: The main "six-pack" muscle, responsible for flexing the spine and controlling the return movement
  • Hip Flexors (Iliopsoas): Critical for bringing the knees toward the chest and maintaining leg elevation
  • Transverse Abdominis: Provides deep core stabilization throughout the movement
  • Obliques: Assist with rotational stability and prevent lateral shifting

Research in exercise science demonstrates that exercises requiring sustained isometric holds combined with dynamic movement patterns, like the Ins and Outs, provide superior assessment of functional core strength compared to isolated exercises. The test's validity comes from its demand for both strength and endurance simultaneously.

Sport-Specific Applications

Core strength measured by the Ins and Outs test translates directly to performance in numerous sports:

Combat Sports (Boxing, MMA, Wrestling): Athletes in these disciplines typically score 50+ repetitions. The movement pattern mimics the core engagement needed for grappling, striking power generation, and defensive positioning.

Gymnastics: Gymnasts often achieve elite scores (75+) due to the sport's emphasis on hollow body positions and pike movements, which are fundamentally similar to the Ins and Outs motion.

Swimming: The hip flexor engagement mirrors the kick mechanics in freestyle and butterfly strokes. Competitive swimmers benefit from scores in the Very Good to Excellent range.

Running and Cycling: While not directly replicating sport movements, strong core endurance improves posture maintenance during long-duration activities, reducing energy waste and injury risk.

Team Sports (Soccer, Basketball, Football): The explosive hip flexion tested in Ins and Outs correlates with sprint acceleration and change-of-direction ability. Athletes should target the Good to Very Good range minimum.

How to Improve Your Ins and Outs Score

Improving your performance requires a systematic approach targeting both the specific movement pattern and general core strength:

Week 1-2 Foundation Phase: Begin with modified versions - allow feet to lightly touch the floor between reps, or reduce range of motion. Perform 3 sets of 10-15 reps, 3 times per week.

Week 3-4 Build Phase: Progress to full range of motion without floor contact. Increase to 3 sets of 15-20 reps. Add complementary exercises: leg raises, dead bugs, and plank variations.

Week 5-6 Peak Phase: Perform maximal tests weekly while maintaining 2 moderate training sessions. Incorporate tempo variations - slow 3-second extensions followed by fast returns.

Supporting Exercises:

  • Hanging leg raises: 3 sets of 10-15 reps
  • V-ups: 3 sets of 15-20 reps
  • Hollow body holds: 3 sets of 30-45 seconds
  • Mountain climbers: 3 sets of 30 seconds

Frequently Asked Questions

What is a good score on the Ins and Outs test?

According to P90X guidelines, completing 25 or more repetitions is considered the minimum standard. Scores of 35-49 reps indicate good core strength, while 50+ reps demonstrates excellent abdominal endurance typical of dedicated athletes.

How often should I test my Ins and Outs score?

Test every 4-6 weeks to track progress while allowing adequate recovery and adaptation time. More frequent testing can lead to overtraining of the hip flexors and diminishing returns.

What muscles does the Ins and Outs test measure?

The test primarily measures the strength and endurance of the rectus abdominis, hip flexors (iliopsoas), and to a lesser extent the obliques and transverse abdominis. It provides a comprehensive assessment of integrated core function.

Can I do the Ins and Outs test if I have lower back pain?

If you experience lower back pain, consult a healthcare professional before attempting this test. The hip flexor engagement can potentially aggravate certain conditions. Modified versions with partial range of motion may be appropriate after clearance.

Why do my hip flexors fatigue before my abs?

This is common and indicates relatively weaker hip flexors compared to abdominals. Include specific hip flexor strengthening exercises like hanging knee raises and lying leg lifts in your training to balance development.

Is the Ins and Outs test only for P90X participants?

While the test is featured in P90X, it can be used by anyone to assess core endurance. The exercise is commonly used in gymnastics, martial arts, swimming, and general fitness programs worldwide.

How accurate is this core strength calculator?

The rating categories are based on established fitness norms and P90X program standards. Individual results may vary based on factors like body weight, limb length, and training history. Use results as general guidance rather than absolute measures.

References

  1. Beachbody, LLC. (2004). "P90X Fitness Guide." Beachbody.
  2. McGill, S.M. (2016). "Low Back Disorders: Evidence-Based Prevention and Rehabilitation." Human Kinetics.
  3. Hibbs, A.E., et al. (2008). "Optimizing Performance by Improving Core Stability and Core Strength." Sports Medicine, 38(12), 995-1008.
  4. Willardson, J.M. (2007). "Core Stability Training: Applications to Sports Conditioning Programs." Journal of Strength and Conditioning Research, 21(3), 979-985.
  5. Kibler, W.B., Press, J., & Sciascia, A. (2006). "The Role of Core Stability in Athletic Function." Sports Medicine, 36(3), 189-198.
  6. American Council on Exercise. (2014). "ACE Personal Trainer Manual." American Council on Exercise.
  7. National Strength and Conditioning Association. (2016). "Essentials of Strength Training and Conditioning." Human Kinetics.

The Test in Action

  • This test is part of the Fit Test for the P90X Home Fitness Workout.
  • The movement pattern is commonly used in gymnastics conditioning and martial arts training.
  • Many military fitness programs incorporate similar exercises for core assessment.

Similar Tests

  • Burpee Test — participants attempt the maximum number of burpees in a set time period.
  • Heart Rate Maximizer — involving repeated jumping jacks over two minutes.
  • Leg Tuck — a similar hanging core strength test used in military fitness assessments.

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