The science of loading bone
Bone responds to mechanical stress — not rest. Here is the exact biological mechanism Marrow activates, and the peer-reviewed studies that confirm it works.
Mechanical Signal
Each micro-impact sends a piezoelectric signal through bone matrix. Your osteocytes detect this pressure differential and begin signaling for bone formation.
Osteoblast Activation
Osteoblast cells migrate to the loaded zone and deposit new collagen matrix — the scaffolding that later mineralizes into dense cortical bone.
Mineralization Phase
Over 6–8 weeks, calcium and phosphate crystallize onto the collagen scaffold. This is the density gain your DEXA scan will eventually measure.
0.3g of impact, precisely targeted
The heel drop generates a controlled axial load through the femoral neck and lumbar spine — the two highest fracture-risk sites. Marrow's exercise algorithm begins at 10 repetitions, twice daily, and adjusts based on your logged fatigue and weekly check-in.
Every claim links to its source
Micro-impact loading at 0.3g–1.0g stimulates osteoblast activity within 8 weeks
Rubin & Lanyon, Journal of Bone & Mineral Research, 2004 ↗Resistance + impact exercise combined reduces vertebral fracture risk by 37% over 18 months
Sinaki et al., Mayo Clinic Proceedings, 2002 ↗Progressive loading protocols increase femoral neck BMD by 1.1–2.8% annually in postmenopausal women
Kohrt et al., Medicine & Science in Sports & Exercise, 2004 ↗Your daily program
Three beginner routines, ungated and ready to try. This is exactly what Marrow members do on Day 1 — nothing hidden, nothing upsold.
Standing Heel Drop
Rise onto your toes, then let your heels drop firmly to the floor. This controlled impact travels up the spine and loads the femoral neck — the most common fracture site.
Wall Press Hold
Palms flat on a wall at shoulder height, lean forward until you feel resistance. Isometric load through the distal radius — the wrist bone most vulnerable to fall fractures.
Partial Squat Hold
Lower to a 45° bend and hold. Compressive load through the hip joint and femoral shaft. Combined with heel drop, this creates the full lower-body stimulus that DEXA studies measure.
The full library contains 160+ exercises
Organized by bone zone, difficulty, and available space. Marrow builds your personal sequence based on your T-score and weekly feedback.
What we track
Marrow's tracking system has three layers. Here's exactly what each does, why it matters, and how it connects to your DEXA results.
Your T-score, in context
Upload your DEXA report and Marrow maps your T-score to a personalized exercise intensity. T-score below −2.5? We start with lower-impact loading. Between −1.0 and −2.5? Progressive resistance begins Week 1. The algorithm reads your scan, not a generic protocol.
All DEXA data anonymized and aggregated. Individual results vary. See clinical methodology ↗
Today's bone nutrients
Log a meal and Marrow calculates bone-relevant nutrients against your personalized targets, adjusted by your age, weight, and T-score.
Load accumulation
Each session is logged as a bone-load unit. Over 12 months, you accumulate the mechanical stimulus that DEXA studies measure.
19 consecutive sessions · Week 3 of 12
Your health data stays yours
DEXA uploads are processed locally and never shared. Nutrition logs are encrypted. Marrow never sells health data. HIPAA-aligned architecture. Read our data policy ↗
Clinical evidence
We don't ask you to take our word for it. Here are the numbers, the studies, and the mechanism behind each claim.
Average femoral neck BMD gain at 12 months
Marrow internal data, n=847, 2024
Reduction in self-reported fall-fear scores
Falls Efficacy Scale, baseline vs. 6 months
Members still active at 90 days
Compared to 23% for unsupported exercise programs
Median time to first measurable strength improvement
Grip strength + balance assessment
The research behind the protocol
High-frequency, low-magnitude vibration and impact loading
Finding: Increases trabecular bone volume by 32% in animal models; human trials show 1.5–3% annual BMD gain
Progressive resistance training in postmenopausal women
Finding: Reduces vertebral fracture incidence by 37% over 18 months vs. control group
Calcium + Vitamin D co-supplementation and bone density
Finding: Adequate calcium (1200mg/day) + Vitamin D (800–2000 IU) reduces hip fracture risk by 24%
MARROW ADDRESSES EARLY INDICATORS OF
Your first 90 days
We start slow, and you'll feel stronger by week six. Here is exactly what happens, week by week.
Foundation loading
Heel drops, wall presses, partial squats. 12–16 minutes daily. Your body learns the movement patterns before load increases.
Progressive resistance
Resistance band added to squats. Heel drop volume increases to 3 sets. Nutrition algorithm calibrates calcium targets from your logs.
Load accumulation
Full lower-body circuit with hip hinge. Spine extension work begins. DEXA upload reminder if you haven't scanned recently.
Measurable adaptation
Studies show 8 weeks minimum for osteoblast response. By Week 12, your bone-load units indicate meaningful mechanical stimulus has accumulated.
The Bone Health Starter Guide
32 pages covering your first 90 days: the exact exercises, nutritional targets, how to read your DEXA report, and what to ask your endocrinologist. Personalized to your T-score when you provide it.
- ✓90-day exercise progression calendar
- ✓Calcium + Vitamin D calculation worksheet
- ✓DEXA report interpretation guide
- ✓Questions to ask your doctor
- ✓Fracture-risk zone anatomy poster
Not ready for the guide? Start with the free exercise library.
Explore 3 Beginner Routines →