Your eight-year-old Sheltie just nailed a clean run at the regional qualifier, but you couldn’t help noticing that recovery took a little longer this time. The post-run stiffness lasted until Tuesday, and those tight collection turns seemed to require more effort than last season. Welcome to the reality of competing with a senior agility dog—where the heart is still 100% puppy, but the joints are filing official complaints. As our canine athletes cross that seven-year threshold, their nutritional needs undergo a fundamental shift. The high-octane performance diet that fueled their prime years now needs recalibrating with targeted mobility support, anti-inflammatory compounds, and careful consideration of whether grains still belong in the bowl.
The grain-free segment has exploded with options promising joint relief and renewed vitality, but not all formulations are created equal when your dog’s still clocking 4.2 YPS on a technical Masters course. In 2026, we’re seeing sophisticated advances in novel protein sources, precision supplementation, and manufacturing transparency that can genuinely extend competitive longevity—if you know what to look for. This guide cuts through the marketing noise to equip you with the veterinary nutrition science and handler wisdom needed to evaluate mobility-supporting grain-free kibbles for your seasoned competitor.
Top 10 Mobility Support Grain-Free Kibble for Competitive Agility Dogs
Detailed Product Reviews
1. Hill’s Science Diet Healthy Mobility, Adult 1-6, Mobility Support, Dry Dog Food, Chicken, Brown Rice, & Barley, 4 lb Bag
Overview: Hill’s Science Diet Healthy Mobility 4lb bag delivers clinically proven joint support for adult dogs through a precise blend of chicken, brown rice, and barley enriched with EPA-rich fish oil. This compact size serves as an ideal trial package for owners assessing palatability and effectiveness before committing to bulk purchases. The veterinary-formulated recipe targets cartilage health and mobility through natural glucosamine and chondroitin sources, making it particularly suitable for small breeds or single-dog households.
What Makes It Stand Out: The #1 veterinarian-recommended status provides immediate credibility, while the precisely balanced minerals strengthen bones alongside joint support. The small bag ensures maximum freshness and allows owners to monitor their dog’s response without financial overcommitment. Made in the USA with trusted global ingredients, it meets rigorous quality standards that budget alternatives often lack.
Value for Money: At $6.00 per pound, this size commands a premium but functions as a low-risk investment. The $23.99 price point is strategic for testing—if your dog rejects it or shows no improvement, you’re not left with 30 pounds of unused kibble. However, it’s 114% more expensive than the bulk option, making it inefficient for long-term feeding.
Strengths and Weaknesses: Pros include veterinary trust, quality ingredients, minimal waste risk, and freshness. Cons feature highest per-pound cost, frequent repurchasing needs for medium-large dogs, and excessive packaging waste for long-term use.
Bottom Line: Perfect for trial periods, small breeds, or budget-conscious testing, though committed owners should size up immediately for savings.
2. Hill’s Science Diet Healthy Mobility, Adult 1-6, Mobility Support, Dry Dog Food, Chicken, Brown Rice, & Barley, 30 lb Bag
Overview: Hill’s Science Diet Healthy Mobility 30-pound bag provides the same veterinary-recommended joint support formula in an economical bulk package ideal for large breeds or multi-dog households. This size delivers comprehensive daily nutrition enriched with EPA-rich fish oil, natural glucosamine, and chondroitin to maintain healthy cartilage and improve mobility in adult dogs aged 1-6. The extensive quantity ensures consistent therapeutic feeding without interruption, critical for seeing measurable joint health improvements over the recommended 30-day minimum trial period.
What Makes It Stand Out: The substantial 30-pound packaging offers the lowest per-pound cost while eliminating frequent reordering hassles. Maintaining the #1 veterinarian-recommended status and USA manufacturing standards, this size demonstrates the brand’s confidence in long-term palatability. The precisely balanced mineral content supports skeletal strength alongside joint care, creating a holistic mobility solution that smaller competitors rarely match at this scale.
Value for Money: At $2.80 per pound, buyers save 53% compared to the 4-pound bag and 25% versus the 15.5-pound option. The $83.99 investment translates to approximately $0.17 per cup—dramatically cheaper than prescription joint diets. While the upfront cost is substantial, dogs consuming 3 cups daily will exhaust this bag in 50 days, making the per-meal expense highly competitive with premium standard diets.
Strengths and Weaknesses: Pros include exceptional per-pound value, reduced environmental waste, and uninterrupted therapy. Cons require significant storage space, high initial investment, and potential staleness for single small dogs.
Bottom Line: The definitive choice for committed owners after dietary acceptance is confirmed. The savings justify the storage commitment.
3. Hill’s Science Diet Healthy Mobility, Adult 1-6, Mobility Support, Dry Dog Food, Chicken, Brown Rice, & Barley, 15.5 lb Bag
Overview: Hill’s Science Diet Healthy Mobility 15.5-pound bag occupies the practical middle ground between trial and bulk sizes, delivering the same veterinary-recommended joint support formula. This package provides EPA-rich fish oil, natural glucosamine, and chondroitin to maintain cartilage health in adult dogs aged 1-6 years. Yielding approximately 62 cups, it suits medium-sized dogs for extended feeding or large breeds for a manageable monthly supply. The resealable packaging maintains freshness while remaining portable enough for most storage spaces.
What Makes It Stand Out: This size uniquely balances cost efficiency with convenience, reducing reorder frequency by 75% compared to the 4-pound bag without requiring dedicated storage bins. Maintaining the #1 veterinarian-recommended status and USA manufacturing standards, it offers the same precise mineral balance for bone strength. For owners seeing initial improvements, this package extends the therapeutic trial period without the commitment of a 30-pound investment.
Value for Money: At $3.74 per pound, buyers save 38% versus the smallest size while paying only a 34% premium over bulk. The $57.99 price translates to approximately $0.23 per cup—competitive with premium mobility supplements alone. It serves as an economical monthly subscription option for single-dog households or those with limited storage capacity.
Strengths and Weaknesses: Pros include manageable weight, improved per-pound pricing, and moderate storage footprint. Cons feature higher lifetime cost than the 30-pound bag and insufficient quantity for multi-dog homes.
Bottom Line: The ideal monthly refill size for confirmed users. Offers sensible savings without bulk storage demands.
4. Wholistic Pet Organics - Hip and Joint Supplement for Dogs & Cats - Cat & Dog Joint Supplement - Green Lipped Mussels, Glucosamine, Chondroitin for Dogs & Cat Mobility Support - 1 Lb - 45 Scoops
Overview: Wholistic Pet Organics Hip and Joint Supplement provides a concentrated powdered formula delivering green-lipped mussel, glucosamine, and chondroitin for advanced mobility support in dogs and cats. This 1-pound container supplies 45 scoops designed to reduce inflammation, improve flexibility, and maintain healthy cartilage in pets suffering from arthritis or hip dysplasia. As a supplement rather than complete diet, it integrates seamlessly with existing food, allowing owners to maintain current feeding routines while adding therapeutic joint support.
What Makes It Stand Out: The New Zealand green-lipped mussel content distinguishes this from conventional joint supplements, providing unique ETA and OTA omega-3 fatty acids with superior anti-inflammatory properties. The powder format enables precise dosing customization for any breed size, from toy breeds to giant dogs, with each scoop delivering consistent therapeutic levels. Its rare canine-feline compatibility makes it economical for multi-species households, while the 45-day supply ensures sustained therapy without frequent reordering.
Value for Money: At $49.99 ($1.11 per serving), this supplement costs more per meal than food-based solutions like Hill’s Healthy Mobility but delivers significantly higher concentrations of active ingredients. For pets requiring intensive support beyond fortified diets, it provides prescription-level nutrition without veterinary markup. The 1-pound container lasts a 50-pound dog approximately six weeks, making it cost-competitive with standalone glucosamine products while offering superior ingredient diversity.
Strengths and Weaknesses: Pros include potent green-lipped mussel, flexible dosing, species versatility, and seamless food integration. Cons require separate food purchase, daily measuring diligence, and potential waste if pet refuses mixed food.
Bottom Line: Superior as a targeted therapeutic booster. Best used in conjunction with quality base diet for maximum joint health impact.
Understanding the Unique Nutritional Demands of Senior Agility Athletes
Competitive agility dogs aren’t typical seniors. While your neighbor’s seven-year-old Labrador might be transitioning to leisurely walks and afternoon naps, your dog is still sprinting, jumping, and performing explosive directional changes that generate forces up to five times their body weight on landing. This creates a metabolic paradox: they need the recovery support of a senior formula but maintain the energy requirements of an athlete. Standard “senior” diets often cut protein and calories too aggressively, accelerating muscle wasting that’s already a risk with age-related sarcopenia. Conversely, maintaining their three-year-old’s performance formula may overload aging kidneys and ignore creeping joint inflammation.
The key lies in strategic nutrient density—delivering more functional ingredients per calorie rather than simply increasing volume. This means evaluating formulations through the lens of a sports medicine specialist, not just a pet nutritionist. Your dog’s food becomes less about basic sustenance and more about a daily therapeutic intervention that must also fuel 90-second bursts of all-out effort.
The Seven-Year Milestone: When Performance Diets Need to Evolve
Seven years marks a critical inflection point for medium and large-breed agility dogs. Research from canine sports medicine shows that synovial fluid quality begins declining around age six, while cartilage repair mechanisms slow measurably by seven. Concurrently, mitochondrial efficiency drops approximately 10% per year after age seven, meaning energy production at the cellular level becomes less robust. Yet many handlers cling to the same fueling strategy that worked at age four.
The transition isn’t about admitting defeat—it’s about smart adaptation. A properly formulated mobility-supporting kibble for senior competitors should reduce inflammatory load while preserving lean muscle mass and supporting cognitive function (because let’s face it, handling mistakes often start when the dog’s brain processing speed lags). Look for formulas that acknowledge this milestone with adjusted calcium-to-phosphorus ratios for aging kidneys, moderate fat levels for sustained energy without pancreatic stress, and elevated antioxidants to combat exercise-induced oxidative damage.
Why Joint Stress Accumulates Faster in Competitive Dogs
Every agility jump creates a concussive force that ripples through your dog’s entire musculoskeletal system. Over a competitive career, a dog performing 200 jumps weekly accumulates over 10,000 high-impact landings annually. This repetitive microtrauma doesn’t just affect obvious joints like hips and shoulders—the entire kinetic chain, from intervertebral discs to carpal joints, experiences accelerated wear compared to pet dogs.
The inflammatory cascade from this chronic stress differs from acute injury inflammation. It’s low-grade, persistent, and can actually interfere with nutrient absorption and muscle protein synthesis. This is why mobility support in kibble must address both structural repair (cartilage building blocks) and systemic inflammation modulation. Simply adding glucosamine to a standard adult formula is like putting premium gas in an engine with a cracked block—it helps, but you’re not fixing the underlying problem.
Decoding Grain-Free: Science vs. Marketing in Canine Nutrition
The grain-free movement has matured from trend to established category, but the science remains nuanced. For agility dogs, the grain-free conversation extends beyond allergy management into the realm of glycemic control, inflammation modulation, and novel nutrient profiles. Legume-based formulations can offer higher protein concentrations and lower glycemic loads than traditional corn or wheat-based diets, which matters when you’re managing energy spikes and crashes during training sessions.
However, “grain-free” is not synonymous with “healthy” or even “appropriate.” Many grain-free kibbles simply substitute grains with other high-starch ingredients like potatoes or tapioca, offering no real metabolic advantage. The true benefit for senior agility dogs lies in formulations that leverage grain-free status to incorporate more animal-based proteins and low-glycemic fiber sources that support stable blood glucose during prolonged competition days.
The DCM Debate: What Agility Handlers Need to Know
The FDA’s investigation into diet-associated dilated cardiomyopathy (DCM) sent shockwaves through the grain-free community, and the conversation continues to evolve in 2026. The current consensus among veterinary cardiologists and nutritionists suggests the issue isn’t grain-free diets per se, but rather formulations that rely heavily on specific legumes (peas, lentils) as primary ingredients while lacking dietary diversity and adequate taurine precursors.
For senior agility dogs, this means scrutinizing ingredient splitting (where “peas” appear as multiple entries like pea protein, pea fiber, and pea starch) and ensuring meat meals appear before legume ingredients. The cardiac demands of agility—where heart rates can exceed 250 BPM during runs—make heart health non-negotiable. Look for brands that publish amino acid profiles showing methionine and cysteine levels, the building blocks for taurine synthesis, and that have proactively conducted third-party cardiac health research on their formulations.
When Grain-Free Makes Sense for Your Senior Competitor
Grain-free becomes particularly relevant for senior agility dogs showing early signs of food sensitivities, which often manifest not as full-blown allergies but as low-grade inflammation affecting recovery. Chronic ear inflammation, persistent foot licking, or post-exercise digestive upset can indicate that traditional grains are contributing to systemic inflammation that undermines joint health.
Additionally, some dogs demonstrate improved muscle glycogen replenishment on lower-glycemic grain-free formulas, particularly those using sweet potatoes or chickpeas as primary binders. The key is ensuring the grain-free choice is driven by metabolic benefit, not marketing. If your dog thrives on a high-quality grain-inclusive performance diet without inflammatory markers, switching to grain-free may offer no competitive advantage. The mobility support ingredients matter far more than the presence or absence of rice.
Mobility Support Matrix: Essential Ingredients That Actually Work
Effective mobility support requires a multi-targeted approach that addresses cartilage integrity, synovial fluid quality, muscle support, and systemic inflammation. The most sophisticated 2026 formulations move beyond token amounts of glucosamine to create a comprehensive matrix of clinically-backed compounds. Understanding therapeutic dosing and synergistic relationships between ingredients separates effective formulas from expensive placebo kibble.
Glucosamine and Chondroitin: The Gold Standard Duo
These foundational joint supplements work synergistically—glucosamine provides the building blocks for glycosaminoglycan synthesis while chondroitin inhibits degradative enzymes that break down cartilage. However, dosage determines efficacy. For a 40-pound agility dog, look for combined levels of at least 800-1000 mg per day from the kibble alone, which typically translates to a guaranteed analysis showing minimum 1000 mg/kg in the finished product.
The source matters too. Glucosamine hydrochloride offers higher purity than sulfate forms, while chondroitin from bovine or porcine cartilage demonstrates better bioavailability than synthetic versions. Some premium formulations now include low molecular weight chondroitin that crosses the intestinal barrier more efficiently. Be wary of products that list these ingredients after salt in the ingredient panel—this indicates minuscule amounts that won’t reach therapeutic levels without additional supplementation.
Omega-3 Fatty Acids: Nature’s Anti-Inflammatory Powerhouse
EPA and DHA from marine sources directly compete with pro-inflammatory omega-6 fatty acids in the prostaglandin synthesis pathway, effectively turning down the volume on exercise-induced inflammation. For senior agility dogs, aim for omega-3 levels providing at least 100 mg EPA+DHA per kilogram of body weight daily. This means a 50-pound dog needs roughly 2,250 mg combined EPA/DHA from their diet.
The omega-6 to omega-3 ratio is equally critical. Many performance diets run ratios as high as 20:1, fueling chronic inflammation. Target formulations with ratios between 5:1 and 8:1, achieved through fish oil inclusion and controlled chicken fat levels. Some cutting-edge 2026 formulas incorporate algae-derived DHA for sustainability and reduced oxidation risk, while others use krill meal for its phospholipid-bound omega-3s that demonstrate superior cellular uptake.
Novel Additions: MSM, Green-Lipped Mussel, and Turmeric
Methylsulfonylmethane (MSM) provides bioavailable sulfur for collagen synthesis and has shown modest pain-relieving properties in canine studies. Look for inclusion around 500-800 mg per day for a medium-sized dog. Green-lipped mussel (Perna canaliculus) offers a unique omega-3 profile plus glycosaminoglycans, but its effectiveness depends on processing—cold-air drying preserves active compounds better than high-heat meals. Effective inclusion rates start at 0.5% of the formula.
Turmeric’s active compound curcumin requires careful formulation to be bioavailable for dogs. Simply adding turmeric powder provides minimal benefit; look for “curcuminoids” with piperine (black pepper extract) or lipid-carrier technology that increases absorption up to 20-fold. The kibble should specify “95% curcuminoid extract” rather than generic turmeric, with inclusion levels around 50-100 mg per day for anti-inflammatory effect.
Protein Priorities: Maintaining Muscle Mass Without Overloading Kidneys
Senior dogs competing in agility lose muscle mass at nearly twice the rate of sedentary seniors when protein intake is inadequate. Yet the myth that high protein damages healthy senior kidneys persists, causing many handlers to inadvertently sabotage their dog’s performance. Current research shows that senior dogs require 25-30% more protein than younger adults to maintain nitrogen balance and prevent sarcopenia.
For a competitive agility dog over seven, target dry matter protein levels between 28-32%—higher than typical senior diets but slightly lower than puppy formulas that might overtax renal function. The key is protein quality over sheer quantity. Highly digestible, animal-sourced proteins with biological values above 90% reduce metabolic waste while delivering essential amino acids for muscle repair after intense training sessions.
The Biological Value Spectrum: From Chicken to Krill
Not all proteins are created equal. Chicken meal, while common, has a biological value around 85-90%. In contrast, egg protein scores a perfect 100, while fish meals and novel proteins like duck or venison often exceed 90%. The amino acid profile matters as much as the score—leucine content drives muscle protein synthesis, while methionine supports taurine production for cardiac health.
Some 2026 formulations now incorporate insect protein (typically black soldier fly larvae) which offers a complete amino acid profile with exceptional digestibility and minimal environmental impact. For dogs with protein sensitivities, hydrolyzed proteins—where the protein molecules are pre-broken into smaller peptides—can provide nutrition without triggering inflammatory responses that manifest as post-exercise stiffness or gastrointestinal distress.
Moderation vs. Restriction: Finding the Sweet Spot for Seniors
The real art lies in balancing protein levels with phosphorus content. As kidneys age, phosphorus clearance declines, and excess phosphorus accelerates renal decline. Quality mobility formulas for senior athletes moderate phosphorus to around 0.8-1.0% on a dry matter basis while maintaining high protein. This is achieved by using animal proteins with naturally lower phosphorus footprints and adding phosphate binders like calcium carbonate.
Watch for formulas that achieve protein levels through plant sources like pea protein. While this boosts the guaranteed analysis number, plant proteins lack the complete amino acid spectrum athletic dogs need and often carry higher phosphorus loads. The ingredient panel should show named meat meals in the top three positions, indicating animal protein drives the formula rather than supplements it.
Beyond the Bag: Manufacturing Quality and Safety Protocols
The most impressive ingredient panel means nothing if manufacturing standards compromise nutrient integrity. For senior dogs where every calorie must count, processing methods determine whether those expensive joint supplements survive extrusion and whether proteins remain digestible. In 2026, leading manufacturers provide unprecedented transparency into their production protocols.
Extrusion temperatures typically reach 300-400°F, which can degrade glucosamine by 30-40% and oxidize omega-3 oils. Premium brands now use post-extrusion coating systems that spray heat-sensitive ingredients onto kibble after cooling, preserving potency. Others employ cold-forming technology for sensitive additives or use stabilizing compounds like mixed tocopherols to protect fatty acids.
Decoding Certifications: What AAFCO, WSAVA, and NASC Really Mean
AAFCO feeding trials, while better than simple formulation analysis, only verify that a diet prevents deficiency in average dogs over six months. They don’t prove efficacy in senior athletes. The WSAVA (World Small Animal Veterinary Association) guidelines for selecting pet foods provide a more rigorous framework, emphasizing companies that employ board-certified veterinary nutritionists, conduct digestibility studies, and practice feeding trials beyond minimum requirements.
The NASC (National Animal Supplement Council) seal indicates quality control for supplements, but its presence on kibble suggests the manufacturer treats their product with supplement-level rigor. Look for brands that publish their quality control data—things like finished product glucosamine assays, peroxide values showing omega-3 freshness, and microbial testing results. This transparency separates marketing from medicine.
Red Flags and Marketing Traps: What to Avoid in 2026
Beware the “kitchen sink” approach where formulas include 30+ ingredients in tiny amounts. This “pixie dusting” allows impressive-sounding ingredient panels without therapeutic levels of any single compound. If a kibble lists 15 different fruits and vegetables after the main protein, you’re likely paying for marketing, not nutrition.
“Proprietary blend” is another red flag when it comes to joint supplements. Reputable companies disclose exact milligram amounts of glucosamine, chondroitin, and other actives. Vague terms suggest they’re hiding sub-therapeutic levels. Similarly, avoid formulas that rely on “natural flavor” as a primary palatant—this often indicates hydrolyzed animal by-products of questionable quality rather than real meat content.
Transitioning Protocols: Switching Foods Without Losing Performance
Never switch a competing dog’s food within six weeks of a major event. The gut microbiome requires 4-6 weeks to fully adapt to a new macronutrient profile, and digestive efficiency directly impacts energy availability. Start transitions during off-season or low-intensity training periods, mixing 25% new food with 75% old food for one week, then 50/50 for two weeks, then 75/25 before full conversion.
Monitor stool quality, training recovery, and body condition weekly. Senior dogs may experience temporary appetite changes during transitions as their metabolism adjusts. Adding a spoonful of canned pumpkin (not pie filling) can ease the fiber transition, while a small amount of kefir or fermented goat’s milk supports beneficial gut bacteria that aid nutrient absorption from the new formula.
The Veterinary Partnership: When to Consult Your Sports Medicine Vet
The relationship with your veterinarian should shift from annual vaccinations to collaborative performance management after age seven. Schedule a baseline wellness panel including SDMA (a sensitive early kidney marker), complete urinalysis, and inflammatory markers like C-reactive protein before switching to a senior mobility formula. This establishes your dog’s normal values.
Repeat these panels three months after transitioning foods to objectively measure impact. Many handlers are surprised to see inflammatory markers drop significantly on properly formulated mobility diets. Your vet can also help interpret whether improvements in performance stem from nutrition or require adjunct therapies like chiropractic care, acupuncture, or targeted rehabilitation exercises.
Frequently Asked Questions
How much glucosamine does my senior agility dog actually need from their kibble?
For therapeutic effect, aim for 20 mg per pound of body weight daily from the food itself. A 40-pound dog needs 800 mg minimum. If the kibble’s guaranteed analysis lists less than 1000 mg/kg, you’ll need additional supplementation to reach therapeutic levels.
Are grain-free diets still safe for senior dogs given the DCM concerns?
Yes, when properly formulated. The issue isn’t grain-free status but excessive legume inclusion and inadequate taurine precursors. Choose brands with meat meals as first ingredients, moderate legume content, and published amino acid profiles showing adequate methionine and cysteine.
Can’t I just keep feeding their regular performance diet and add joint supplements?
You can, but it’s less efficient. Separate supplements often have poor palatability and variable absorption. Integrated kibble ensures consistent dosing and uses food-based carriers that enhance bioavailability. Plus, senior-specific formulas address multiple aging pathways simultaneously.
How long before I see improvements in mobility and recovery?
Expect 4-6 weeks for systemic inflammation reduction and 8-12 weeks for measurable cartilage improvements. Many handlers report better next-day recovery within 2-3 weeks, but structural changes in joints require consistent nutrient delivery over time.
What if my dog has early-stage kidney disease—can they still compete on mobility kibble?
Yes, with veterinary guidance. Look for formulas with phosphorus below 0.8% and added omega-3s, which may slow renal progression. Your vet might recommend a phosphorus binder and more frequent monitoring, but many early-stage dogs maintain performance on adjusted senior athlete formulas.
Does kibble size really matter for senior agility dogs?
Absolutely. Dental health impacts systemic inflammation, and many seniors have compromised teeth. Smaller kibble (around 1/2 inch diameter) encourages thorough chewing, improving digestion and reducing choking risk during rapid eating between runs at trials.
Should I consider raw or fresh food instead of kibble for my senior competitor?
While fresh food offers excellent digestibility, maintaining consistent nutrient levels for mobility support is challenging. If you prefer fresh, choose a commercially prepared, complete-and-balanced fresh food with added joint supplements, not homemade diets that often lack therapeutic nutrient levels.
How do I justify the cost difference to my training partner who feeds budget kibble?
Calculate cost per therapeutic nutrient, not cost per pound. A $90 bag with therapeutic levels of multiple joint compounds replaces $40+ in separate supplements that have lower compliance and absorption. Factor in reduced veterinary intervention costs and extended competitive career length.
What’s the biggest mistake handlers make when choosing senior mobility food?
Choosing based on senior labeling rather than athlete-appropriate nutrition. Many “senior” formulas cut protein and calories too drastically, accelerating muscle loss. Your dog needs a senior athlete formula, not a retirement diet.
My dog refuses to eat the new mobility-support kibble. What now?
First, ensure gradual transition. If refusal persists, the kibble may use low-quality palatants. Try a different protein base or add a small amount of warm water to release aromas. Some dogs prefer the new food as training treats before accepting it as meals. Never force a switch—appetite drives nutrient intake, and stress undermines joint health.