In fitness and rehabilitation settings, a new pattern is emerging. Clients taking GLP-1 medications, such as semaglutide or tirzepatide, are losing weight, moving more easily, and often re-engaging in exercise for the first time in years. Walking feels better, and stairs are less of a fight. Confidence rises quickly, and increases in training volume soon follow. Witnessing this 180-degree lifestyle shift is incredible, as individuals transform from a sedentary existence to a vibrant, newfound interest in health and fitness.
Dr. Meredith Butulis, DPT, OCS, CEP, CSCS, CPT, PES, CES, BCS, Pilates-certified, Yoga-certified, has been working in the fitness and rehabilitation fields since 1998. She is the author of Your Wellness Makeover and the Mobility | Stability Equation series, Host of the “Fitness Comeback Coaching Podcast,” and Sports and Orthopedic Physical Therapist serving Sarasota Memorial Health Systems. She shares her background to help us reflect on our professional fitness practices from new perspectives that can help us all grow together in the industry. Grab a copy of her new book, The Durable Athlete: The Trainer's Guide to Long-Term Athlete Development for Weekend Warriors Over 40. Instagram: @doc.mnb
However, alongside that progress, a second pattern is showing up just as consistently. New musculoskeletal complaints are appearing in bodies that are otherwise appearing healthier. Observations include low back pain in clients who have never had back issues, or lateral hip pain after a few weeks of returning to a walking program. In other cases, the upper body is more affected. Perhaps shoulder discomfort appears shortly after returning to resistance training. These are not severe injuries, but they are noticeable enough to interrupt momentum.
When observing this, the easy assumption is to blame the medication. Yet, making that jump ignores the mechanical reality. At this point, there is no strong evidence that GLP-1s impair tendon or muscle tissue directly. Instead, exploring this through a different, highly practical coaching lens provides better answers.
The Adolescent Growth Spurt Analogy
To understand the client experience, consider another period of profound, rapid physical change: the adolescent growth spurt. When teenagers grow rapidly, their bodies are thrown into a state of structural chaos. They experience significant changes in neuromuscular coordination. Tendons and connective tissues struggle to keep up with bone growth, and altered biomechanics make overuse injuries a prime concern.
Clients utilizing GLP-1 medications are experiencing a reversal of growth. The body is changing faster than it is adapting. Body weight changes faster than the tissues’ ability to tolerate and distribute that load. Every kilogram lost changes how force moves through the system. Hips handle gait differently, the trunk manages load differently, and the shoulder stabilizes repetition differently. As in adolescence, the GLP-1-enhanced body is underprepared for the changing physiological environment.
The Metabolic Reality: Reversibility and the Catabolic State
When individuals lose significant weight, the assumption is often that everything in the system becomes easier. In one sense, that is true, because less body mass means less absolute load on joints. But the principle of reversibility cannot be ignored. Even with fat loss, lean mass is often lost. Rapid weight loss places the body in a highly catabolic environment where tissue is broken down for energy. Furthermore, as overall mass drops rapidly, Basal Metabolic Rate will inevitably decrease. If left unchecked, this catabolic state can heavily consume the muscle tissue that provides joint centering, force distribution and deceleration control.
To counter this and foster an anabolic environment, nutrient timing and specific coaching interventions become critical. Adequate fueling around workouts signals the body to preserve muscle. Appetite suppression, however, is a common side effect of GLP-1. This can lead individuals to eat less than expected, often causing protein intake to drift down unnoticed. Optimal protein intake typically falls between 1.6 and 2.2 grams per kilogram of body weight to support muscle retention during caloric deficits. However, a significant risk arises when there is an exclusive hyperfocus on protein. Neglecting carbohydrates and healthy fats compromises hormonal balance, depletes glycogen stores necessary for training energy, and severely impairs recovery. A balanced macronutrient profile is non-negotiable for sustaining a newly active lifestyle.
Plug and Play Strategies for the Client Using GLP-1s
Muscle adapts relatively quickly over weeks. Tendons and connective tissue adapt more slowly over months. Therefore, a person can feel better almost immediately while still being structurally underprepared for increased training volume or complexity. That gap is where the coaching focus must be directed. Here is how intake, assessment, and programming can adjust to meet these unique needs.
1. Intake: From Snapshot to Change Story
Because of the sudden lifestyle shift, always start by completing a new PAR-Q+ to screen for any underlying health conditions. From there, the initial prospective client conversation needs to shift from a baseline snapshot to painting a picture of the client’s story of change.
In addition to typical questions, fitness professionals gain a more complete picture by asking questions such as:
• "How fast is body weight changing?" Was it steady or rapid, meaning more than 1 to 2 pounds per week consistently? These questions matter because rapid loss, combined with new exercise, creates a high mismatch risk between load and tissue adaptation.• "What changed at the same time?" Has the daily step count doubled without noticing? Questions like this may reveal multiple simultaneous stressors without a clear recovery strategy.• "What do meals actually look like on a normal day?" Are meals being skipped due to appetite suppression? A red flag pattern is low appetite combined with increased activity, which creates a poor recovery environment for optimizing lean mass retention.
2. Assessment: Test Tolerance, Not Strength
Traditional max-output testing is less useful here than testing how the system holds up as volume increases. The goal is to look for fatigue behavior, not maximal strength. Here are some helpful examples:
• Single-leg control under repetition: Instead of a 1-RM squat or leg press, watch 8 to 12 lunge reps per side. Look for quality drop-offs, such as pelvic drop, trunk shift, or foot collapse under fatigue. To add specificity, perform this on a slightly unstable surface, such as an Airex pad. This tells the coach how gait and walking tolerance will behave when weekly volume increases.• Trunk endurance over time: Instead of counting reps to fatigue on the initial assessment, have clients perform appropriately scaled front plank and side plank variations. Watch for a loss of scapular, rib, and pelvic alignment over time. Specifically, track the number of seconds until a slight compensation appears. This indicates whether the core can handle cumulative daily loads.• Monitor Recovery: Ask clients to rate their soreness on a scale of 0-10 48 hours after activity. If their rating is higher than 5/10, it may indicate that recovery strategies are lagging, or progressions are exceeding the body’s current capacity.
3. Programming: Slow the System Down
This is where coaching gets pulled off track. For many clients taking GLP-1’s, cardiovascular tolerance improves fast, and walking feels easier almost immediately. However, connective tissue and muscular resilience do not adapt at the same speed. Here are a few tips from which to build:
• Keep resistance training as the anchor: Maximizing lean muscle mass requires resistance training, and consistent training can be a key to building capacity. Consistency would typically aim for at least 2 to 3 days per week. On these resistance-training days, focusing on moderate loads and controlled eccentric contractions can help lay the foundation for both muscle and tendon strength. For example, a client could perform 3-5-second eccentric lowering phases during total-body lifts like goblet squats. This builds structural resilience. The goal is to preserve the structure under gradually increasing stressors for positive adaptation.• Progress cardio carefully: Cardiovascular activity builds reps quickly, making it a breeding ground for overuse injuries if biomechanical weaknesses are present. In general, progression is safer when it focuses on either duration, frequency, or intensity, but never all three at once.• Treat coordination as the first fatigue signal: Before pain shows up, slower transitions, reduced balance, or compensations will appear toward the end of sets. That is the early warning system, as opposed to waiting for form failure or high levels of lingering soreness.
Navigating the Long-Term Journey
Supporting this demographic over the months and years requires candid conversations about the long-term. This may include the fact that science on GLP-1s is emerging, that rapid weight-loss-associated skin sagging cannot be spot-trained away, and that the principles of reversibility upon stopping GLP-1 medications remain at play.
Overall, the goal is not to slow progress; it is to match it. When strength, coordination, and progression pace align with tissue capacity, individuals do not just lose weight; they also improve their performance and motivation to adopt long-term wellness lifestyles.
