Five simple exercises performed for just 30 seconds each can transform your core strength without a single crunch or piece of equipment. Online trainer James Stirling’s bodyweight routine targets every major core muscle group through movements that actually translate to real-world strength and stability.
The workout consists of Hollow Hold, Back Extension, Leg Lifts, Shoulder Taps, and Copenhagen Plank—each performed for 30 seconds (except the Copenhagen Plank at 20 seconds per side). Complete five rounds with 30-second rests between exercises and one-minute rests between rounds, and you’ll have invested just 25 minutes in building the kind of core strength that improves everything from your posture to your athletic performance.
This isn’t another trendy fitness fad promising overnight transformation. It’s a methodical approach to core development that works your entire midsection as an integrated unit rather than isolating individual muscles. The routine fires up your rectus abdominis, obliques, hip flexors, inner thighs, and crucially, your posterior chain—the often-neglected muscles that provide the foundation for genuine core stability.
What makes this routine particularly effective is its emphasis on time under tension and functional movement patterns. Each exercise challenges your core to maintain stability while your body moves through different planes of motion, exactly the kind of strength you need for daily activities and athletic performance.
The Science Behind Equipment-Free Core Training
Building core strength without equipment isn’t just convenient—it’s often more effective than machine-based alternatives. Bodyweight exercises force your stabilizing muscles to work harder because they can’t rely on external support systems. Your core has to engage in complex, multi-directional patterns that mirror real-world movement demands.
The hollow hold, for instance, creates what exercise physiologists call “anti-extension” strength—your core’s ability to resist unwanted spinal movement. This translates directly to better posture, reduced back pain, and improved performance in virtually every athletic activity. Similarly, the Copenhagen plank targets the often-overlooked adductor muscles, which play a crucial role in hip stability and injury prevention.
Research consistently shows that compound movements that challenge multiple muscle groups simultaneously produce superior results compared to isolated exercises. This workout embodies that principle by incorporating exercises that require coordination between your core, hips, and shoulders.
Breaking Down the Five-Exercise Formula
Hollow Hold (30 seconds): This exercise might look deceptively simple, but it’s arguably the most challenging movement in the routine. You’ll lie on your back, press your lower back into the floor, and lift your shoulders and legs off the ground while maintaining a curved spine position. The key is creating a “hollow” shape with your torso while keeping your core rock-solid.
The hollow hold builds what trainers call “anterior core strength”—the ability of your front abdominal muscles to work in harmony with your hip flexors. This combination is essential for activities ranging from running to lifting overhead. If you’re new to this movement, bend your knees slightly to reduce the intensity until you build sufficient strength.
Back Extension (30 seconds): Often overlooked in core routines, the back extension targets your posterior chain—the muscles along your spine that counterbalance your front abdominals. You’ll lie face down and lift your chest and legs simultaneously, creating a gentle arch in your back.
This exercise is particularly valuable for people who spend long hours sitting, as it strengthens the exact muscles that become weak and overstretched from prolonged sitting. Strong back extensors are essential for maintaining proper posture and preventing the rounded-shoulder, forward-head position that plagues desk workers.
Leg Lifts (30 seconds): This movement specifically targets your lower abdominals and hip flexors while challenging your ability to maintain spinal stability. You’ll lie on your back and lift your legs from the ground to a 90-degree angle, then lower them slowly without letting them touch the floor.
The controlled lowering phase (called the eccentric portion) is where the real strength-building happens. Your core has to work overtime to prevent your lower back from arching as your legs approach the ground. This translates to better control during activities like climbing stairs or getting out of bed.
Shoulder Taps (30 seconds): Moving into a plank position, you’ll alternate touching your opposite shoulder while maintaining a stable plank. This exercise builds “anti-rotation” strength—your core’s ability to resist twisting when external forces try to rotate your spine.
The shoulder taps also challenge your proprioception (body awareness) and coordination. Your core has to work harder to maintain stability when you remove one point of contact with the ground. This type of unilateral training is crucial for developing the kind of core strength that transfers to sports and daily activities.
Copenhagen Plank (20 seconds each side): Named after the Danish research facility where it was popularized, this exercise targets your adductor muscles (inner thighs) while challenging your lateral core stability. You’ll lie on your side and support your body weight with your forearm and the inner edge of your top foot.
This movement addresses a common weakness in most people’s training—lateral stability. Your adductors play a crucial role in preventing knee injuries and maintaining proper hip alignment during activities like running, cutting, and jumping.
The Myth of Endless Crunches: Why This Approach Works Better
Here’s where conventional core training wisdom gets turned on its head: crunches and sit-ups aren’t just ineffective—they can actually be counterproductive for building real-world core strength. The repetitive spinal flexion involved in crunches can contribute to disc problems and doesn’t translate to functional movement patterns.
Traditional ab exercises like crunches primarily work your rectus abdominis in isolation, but your core doesn’t function in isolation during daily activities. When you carry groceries, play sports, or even stand up from a chair, your core works as an integrated unit to provide stability and transfer force between your upper and lower body.
This five-exercise routine addresses that reality by training your core the way it actually functions. Instead of repeatedly flexing your spine, you’re teaching your core to maintain stability while your limbs move independently. This approach builds what exercise scientists call “functional core strength”—the kind that actually improves your quality of life.
Moreover, the time-under-tension approach used in this routine (holding positions for 20-30 seconds) builds muscular endurance alongside strength. Your core muscles are primarily composed of slow-twitch fibers designed for endurance rather than explosive power, making sustained holds more appropriate than high-repetition movements.
Modifications for Every Fitness Level
The beauty of this routine lies in its scalability. Every exercise can be modified to match your current fitness level, making it accessible whether you’re a complete beginner or an experienced athlete looking to supplement your training.
For the hollow hold, beginners can bend their knees to reduce the load on their hip flexors and core. As you get stronger, you can straighten your legs and eventually extend your arms overhead to increase the challenge. Advanced practitioners can add small rocks or pulses to intensify the movement.
The back extension can be made easier by keeping your feet on the ground and only lifting your chest, or by placing a pillow under your hips for support. To make it more challenging, you can extend your arms overhead or hold the lifted position for longer periods.
Leg lifts become more manageable when you bend your knees, reducing the lever arm and making the movement less demanding. As you progress, you can straighten your legs and eventually slow down the lowering phase to increase difficulty.
If shoulder taps feel too challenging in a full plank, you can modify by dropping to your knees or elevating your hands on a sturdy surface like a couch or coffee table. Advanced practitioners can add a push-up between each tap or perform the movement with their feet elevated.
The Copenhagen plank can be modified by placing your bottom knee on the ground for additional support, or by keeping your top leg bent rather than straight. As you build strength, you can progress to lifting your bottom leg off the ground or adding small leg lifts.
The Muscle Groups You’re Actually Working
This routine targets every major component of your core system, not just the “mirror muscles” that people typically associate with ab workouts. Your rectus abdominis (the six-pack muscles) handles spinal flexion and provides anterior stability. Your obliques, both internal and external, control rotation and lateral flexion while providing side-to-side stability.
Your transverse abdominis, often called the body’s natural weight belt, acts as a deep stabilizer that increases intra-abdominal pressure and supports your spine. This muscle is particularly important for people with back problems, as it provides crucial support for the lumbar spine.
The hip flexors work heavily during leg lifts and hollow holds, connecting your core to your lower body and playing a crucial role in activities like running, jumping, and climbing stairs. Strong hip flexors also contribute to better posture by helping maintain proper pelvic alignment.
Your erector spinae and other back muscles get significant attention through the back extension and Copenhagen plank. These muscles are essential for maintaining upright posture and preventing the forward head position that develops from prolonged sitting.
Even your adductors (inner thigh muscles) get targeted through the Copenhagen plank, which addresses a common weakness in most people’s training. Strong adductors contribute to hip stability and can help prevent knee injuries during sports and daily activities.
Progressive Overload Without Equipment
One challenge with bodyweight training is creating progressive overload—the gradual increase in training stress that drives adaptation. This routine addresses that challenge through several built-in progression methods that don’t require additional equipment.
Time-based progression is the most straightforward approach. Start with shorter holds (perhaps 15-20 seconds) and gradually work up to the full 30-second durations. Once you can complete all five rounds at full duration, you can extend the holds to 45 seconds or even a full minute.
Volume progression involves adding additional rounds. While the routine calls for five rounds, you can start with three rounds and gradually build up. Advanced practitioners might eventually work up to seven or eight rounds for a more intensive workout.
Intensity progression comes through movement modifications. Each exercise has multiple variations that increase difficulty without requiring equipment. For example, you can progress from a bent-knee hollow hold to a straight-leg version, then to an extended-arm version, and finally to a hollow body rock.
Tempo manipulation offers another progression avenue. Slowing down the movement (especially the lowering phases) increases time under tension and builds strength. You might perform leg lifts with a three-second lowering phase, or hold the top position of the back extension for additional seconds.
Integration with Your Existing Routine
This five-exercise routine works exceptionally well as either a standalone workout or as a supplement to your existing training. If you’re already following a structured fitness program, this routine can serve as an excellent warm-up to activate your core before more intensive training.
For people focused on strength training, performing this routine 2-3 times per week on non-consecutive days provides excellent core development without interfering with recovery from heavier lifting sessions. The bodyweight nature of the exercises means they won’t significantly impact your ability to perform deadlifts, squats, or other compound movements.
Runners and endurance athletes can benefit from incorporating this routine twice weekly to build the core stability essential for efficient movement patterns and injury prevention. The anti-rotation and anti-extension strength developed through these exercises directly translates to better running form and reduced energy waste.
Those following yoga or Pilates practices will find this routine complements their existing training beautifully. The emphasis on controlled movement and mind-muscle connection aligns perfectly with both disciplines while providing a more intense strength-building stimulus.
Beyond the Basics: Long-Term Development
While this five-exercise routine provides an excellent foundation, long-term core development requires progressive challenge and variation. Once you’ve mastered the basic movements and can complete five rounds with perfect form, consider incorporating additional elements to continue your progress.
Compound movements like deadlifts, squats, and overhead presses naturally engage your core while building full-body strength. These exercises teach your core to function as part of a complete movement chain rather than in isolation.
Loaded carries such as farmer’s walks, suitcase carries, and overhead carries challenge your core’s ability to maintain stability under load while moving through space. These exercises build the kind of real-world core strength that translates directly to daily activities.
Rotational movements like wood chops (which can be performed with a medicine ball or even a gallon of water) add another dimension to your core training by challenging your ability to generate and control rotational forces.
The key to long-term success is consistency rather than intensity. Performing this routine three times per week with perfect form will yield better results than sporadic high-intensity sessions. Your core responds best to frequent, moderate stimulation rather than occasional extreme challenges.
This equipment-free approach to core training represents a return to fundamental movement patterns that have proven effective for generations. By focusing on quality over quantity and function over appearance, you’ll build the kind of core strength that truly enhances your daily life and athletic performance.
