Good Mornings: Loading Guidelines, Biomechanics, and Safety

What percentage of squats should you do on good mornings?

While there isn't a direct, universally recommended percentage of your squat max to use for good mornings due to their distinct biomechanics and inherent risk profile, loads should generally be significantly lighter, prioritizing impeccable form and muscular tension over absolute weight.

Understanding the Good Morning Exercise

The good morning is a powerful, yet often misunderstood, accessory exercise for developing the posterior chain—specifically the hamstrings, glutes, and spinal erectors. It involves a controlled hip hinge movement where the torso bends forward while maintaining a rigid, neutral spine, with a barbell typically resting across the upper back, similar to a back squat.

• Purpose and Primary Movers: The primary goal of the good morning is to strengthen the muscles responsible for hip extension and spinal stability. It heavily targets the hamstrings and glutes as prime movers for hip extension, while the erector spinae muscles work isometrically to maintain a neutral spinal position against significant leverage.
• Biomechanics: The good morning creates a long lever arm with the torso, placing substantial shear forces on the lumbar spine. This is distinct from the more compressive forces experienced during a squat. This leverage makes the good morning an excellent exercise for building strength in the stretched position of the hamstrings and for developing robust core and lower back stability.

Why the "Percentage of Squat" Question Arises

It's common for lifters to seek a direct correlation between their strength in one lift and another, especially when both involve a barbell and target similar muscle groups (like the lower body and back). The question of "what percentage of squats should I do on good mornings?" stems from this desire for a simple, quantifiable metric to guide loading. However, equating the two movements directly can be misleading and potentially dangerous.

Key Biomechanical Differences: Squats vs. Good Mornings

To understand why a direct percentage translation is inappropriate, it's crucial to highlight the fundamental biomechanical distinctions:

• Joint Action: A squat involves significant flexion and extension at both the hip and knee joints, making it a knee-dominant exercise with considerable quad involvement. A good morning, conversely, is primarily a hip hinge movement with minimal knee flexion, making it a hip-dominant exercise.
• Loading Profile: During a squat, the load is primarily vertical, placing compressive forces on the spine. While shear forces exist, they are less pronounced than in a good morning. In a good morning, as the torso approaches parallel to the floor, the horizontal component of the bar's weight creates substantial shear stress on the lumbar spine. This is a critical difference in spinal loading.
• Muscle Emphasis: While both engage the glutes and erector spinae, the squat heavily recruits the quadriceps. The good morning places a much greater emphasis on the hamstrings (especially in their lengthened position) and the isometric strength of the erector spinae to prevent spinal flexion.
• Stability Demands: Both exercises require core stability, but the good morning demands an exceptionally high degree of isometric strength from the spinal erectors and transverse abdominis to maintain a neutral spine against the strong bending moment.

The Perils of Direct Percentage Translation

Attempting to use a direct percentage of your squat 1-Rep Max (1RM) for good mornings can lead to several issues:

• Increased Injury Risk: The significant shear forces and the unique leverage of the good morning mean that your lumbar spine and posterior chain will be challenged in a very different way than during a squat. A load that feels manageable as a percentage of your squat could be excessively heavy and dangerous for a good morning, leading to spinal rounding and potential injury.
• Mismatch in Limiting Factors: Your squat strength might be limited by your quads or overall leg drive. Your good morning strength, however, is more likely to be limited by hamstring flexibility/strength, glute engagement, or, most critically, the isometric strength and endurance of your spinal erectors. Applying a squat percentage overlooks these specific limiting factors.
• Technique Compromise: Overloading the good morning prematurely almost invariably leads to a breakdown in form, such as spinal rounding, excessive knee bend, or an inability to control the eccentric phase. This negates the exercise's benefits and amplifies risk.

Establishing Appropriate Loading for Good Mornings

Given the above, a more nuanced and cautious approach to loading good mornings is essential.

• Prioritize Technique Above All: Flawless form is non-negotiable. Before adding any significant weight, ensure you can perform the movement with a perfectly neutral spine, controlled descent, and strong hip hinge.
• Start Extremely Light: For most individuals, especially when first learning the movement, begin with just the empty barbell (45 lbs/20 kg) or even a PVC pipe or light dumbbells to master the pattern.
• Focus on Rate of Perceived Exertion (RPE): Instead of percentages, use RPE as your primary guide. Aim for sets that feel like an RPE of 6-8 (meaning you could have performed 2-4 more repetitions with good form). This ensures you are challenged but not pushed to failure, where form is most likely to break down.
• Progressive Overload, Cautiously: Once you can consistently perform sets with perfect form at a given weight, increase the load incrementally. Small jumps (e.g., 2.5-5 lbs/1-2 kg) are best. The goal is consistent, slow progress while maintaining technique.
• Listen to Your Body: Any sharp pain, especially in the lower back, is a definitive signal to stop, reduce the weight, or re-evaluate your form.

General Guidelines and Starting Points

While a direct percentage of your squat isn't recommended, here are some general guidelines for experienced lifters who have already mastered the good morning form:

• For experienced lifters with impeccable form and a very strong posterior chain, working sets for good mornings might range from 20-40% of their 1RM back squat. However, this is a highly individualized range and should never be a starting point for anyone new to the exercise or with less-than-perfect form.
• Beginner Recommendation: Focus solely on bodyweight, a PVC pipe, or an empty barbell until the hip hinge pattern is deeply ingrained and spinal neutrality can be maintained effortlessly.
• Intermediate Recommendation: Start with an empty barbell and gradually add weight in the smallest possible increments (e.g., 2.5-5 lbs or 1-2 kg per week/session) while strictly adhering to RPE and form checks.

Important Note: These "percentages" are descriptive of what advanced lifters might handle, not prescriptive for how you should load. Your individual strength, flexibility, and spinal health will dictate your appropriate load.

Safety Considerations and Proper Form

• Neutral Spine: This is paramount. Maintain a rigid, neutral spine throughout the entire movement. Avoid any rounding of the lower back, especially at the bottom of the movement.
• Bracing: Before initiating the movement, take a deep breath into your abdomen and brace your core tightly. This creates intra-abdominal pressure, helping to stabilize the spine.
• Controlled Movement: Execute the good morning slowly and deliberately, especially during the eccentric (lowering) phase. Avoid using momentum.
• Range of Motion: Only descend as far as your hamstring flexibility and spinal control allow. The goal is to feel a deep stretch in the hamstrings without compromising your spinal position. For most, this means stopping when your torso is parallel to the floor or slightly above.
• Spotting and Safety: Perform good mornings inside a power rack with safety pins set appropriately. If you lose control or feel your form breaking down, you can safely dump the bar onto the pins.

Integrating Good Mornings into Your Training Program

Good mornings are best used as an accessory exercise to complement your main compound lifts.

• Frequency: 1-2 times per week is generally sufficient for most lifters.
• Volume: Typically, 2-4 sets of 6-12 repetitions are performed. The higher rep ranges can help build muscular endurance in the spinal erectors.
• Placement: They are often performed after your main compound lifts (e.g., squats or deadlifts) on leg days or posterior chain-focused training days.

Conclusion

The good morning is an exceptional exercise for building a strong, resilient posterior chain and improving spinal stability. However, it is a demanding movement with a unique risk profile that necessitates a cautious approach to loading. Disregard the temptation to directly translate percentages from your squat maximum. Instead, prioritize flawless technique, listen intently to your body, utilize RPE to gauge effort, and practice slow, incremental progressive overload. By respecting the biomechanics of the good morning, you can safely harness its power to enhance your overall strength and athletic performance.