Musculoskeletal Health and Physical Function Hub

Navigator for the muscle-bone-function domain — the substrate of the older-adult health-lever question: what predicts decline (muscle mass, strength, function, sarcopenia), what the modifiable levers are (resistance training, protein, fall prevention), and where bone supplementation does and does not help. The through-line is the metric-vs-lever distinction — most muscle measures predict mortality partly as markers of underlying health, and few are proven treatment targets — and the deficiency-vs- enhancement split on the bone side (Deficiency Repletion vs Enhancement).

Muscle — mass, strength, and function (as predictors)

• Sarcopenia Definition and Diagnosis — how age-related muscle loss is defined and diagnosed, and what to measure: mass, strength, or function (EWGSOP2 screens strength first)
• Grip Strength and Mortality — how strongly grip (the cheap proxy for muscle function, distinct from mass) predicts all-cause + cause-specific mortality (Celis-Morales, UK Biobank n=502,293); a cheap risk metric, out-ranking blood pressure and self-reported activity in-model — but a predictor, not a proven lever
• Low Muscle Mass and Mortality — whether low appendicular muscle mass predicts all-cause mortality independent of strength (de Santana SR-MA: yes, SMD -0.18) — mass and strength are different quantities, and strength tends to out-predict mass
• Muscle-Strengthening Activity and Mortality — whether strength training reduces mortality and disease independently of aerobic activity, and at what dose — the interventional test of the observational muscle-mortality associations above

Building and keeping muscle (the levers)

• Anabolic Resistance — the mechanism behind the older-adult protein target: aging blunts the muscle-protein-synthesis response to a protein meal, raising the per-meal leucine and dose thresholds; resistance training partially restores that sensitivity
• Resistance Training Prescription - Load Sets and Frequency — how to program RT (load for strength, volume for hypertrophy), the minimal effective dose, and why any-RT-beats-none dwarfs the between-protocol gap; the closest-to-patient-important signal is physical function in older adults
• Power Training and Physical Function in Older Adults — whether training MODE (high-velocity power vs conventional slow strength) matters for physical function in older adults: power beats strength on function tests (SMD 0.43, GRADE HIGH) and on muscle power (0.99), but no trial measured daily-life activity or falls, so the function->participation link stays a gap
• Detraining and Residual Effects in Older Adults — the retention half of the dose question: when an older adult STOPS, functional-capacity gains persist at a medium effect over control through a 1-2 month layoff (ES 0.88), mode-agnostically; bigger prior gains and younger age retain better, but the decay time-course and any reduced maintenance dose are unestimated (a layoff is not a reset)
• Supervised vs Unsupervised Exercise — the delivery-format decision: supervised beats unsupervised (home) only slightly and mostly non-robustly in older adults, and attendance was equal (81%) in both arms, so the edge is a dose/intensity confound, not supervision as such; knee extension strength is the one robust exception; UNSUP is the realistic default, especially vs no exercise
• Blood Flow Restriction Training — the route-(c)/(e) workaround for the person who cannot load heavy (older, comorbid joints/bones, rehab): a limb cuff during light-load work reaches heavy-load-comparable hypertrophy (ES 0.21, ns vs HL) but below-heavy-load strength (ES -0.42), and beats light load alone on strength (ES 0.86); low confidence (11 studies, n=238, mostly PEDro 4), safety in older adults insufficient-evidence
• Exercise Interventions and Sports Injury Prevention — which exercise prevents sport injury: strength training cuts injuries to <1/3 (RR 0.315, the standout), proprioception helps, STRETCHING does not (tight null); RT’s one causal-grade patient-important outcome, in young athletes
• Tendon Adaptation to Mechanical Loading — the connective-tissue layer under the strength-training benefit: high load MAGNITUDE (not contraction type) stiffens tendon (stiffness SMD 0.70; high- vs low-intensity 0.90 vs 0.04), mostly via material not size change; outcomes are surrogates (no injury measured), and tendon adapts SLOWER than muscle — the rate mismatch that argues for a gradual load ramp, most of all in the deconditioned/obese novice; evidence is young active men (Bohm 27-study SR-MA)
• Training Load Progression and Running Injury — the epidemiological counterpart: does ramping running volume too fast cause injury, and is the “10% rule” sound? INSUFFICIENT evidence for the causal claim (4 heterogeneous studies, 3 weakly positive, no meta-analysis) and NO evidence for the 10% figure — the one study testing it found 10% and 24% weekly increases equivalent (HR 0.8, CI 0.6-1.3); ramp gradually for mechanism/low-regret reasons, not the number; novice/amateur runners only (Damsted 2018 SR)
• Stress Fracture Risk Factors in Runners — the BONE-stress-injury sibling (Wright 2016 gold SR-MA, 8 studies/4 cohorts): only prior stress fracture (pooled OR 4.99) and female sex (OR 2.31) are supported; training volume/BMD/menstrual/nutrition all conflicting or single-study, biomechanics unstudied. Two beyond-summary moves — the lean/female host-factor set INVERTS in the obese novice (high mass -> high BMD -> bone-stress risk falls, soft-tissue/joint risk rises), and a type-A convergence with Damsted that training-load injury heuristics (volume rule + 10% rule) lack evidence; a DISTINCTION from Damsted (absolute volume + host factors -> bone, vs load-change -> any RRI), not a tension
• Biomechanical Risk Factors for Running Injury — the biomechanics/gait-screening cell (Peterson 2022 gold SR+MA, 30 prospective studies / 3404 runners / 100+ factors): headline NULL — 23/25 pooled analyses found no relationship; biomechanical/MSK measurements are not supported as RRI predictors and gait/strength screening is not justified for injury prevention. Only 2 trivial-effect pooled signals (knee ext strength SMD -0.19; hip adduction velocity MD -12.80), both clinically unimportant. Type-E convergence with Wright that intrinsic-trait screening is low-yield; the load-capacity causal frame points the modifiable signal at training load, not static anatomy. Non-elite-runner stratum does not transport to the obese/untrained novice
• Protein and Resistance Training for Muscle and Strength — whether protein supplementation adds to resistance training for muscle and strength, how much, and for whom
• Protein Intake for Older Adults — how much protein an older adult needs, daily and per meal, and why it is complementary to the training stimulus (cross-ref: Protein and Supplements Hub)
• Resistance Training During Caloric Restriction — the muscle-preservation lever for the obese older adult who is dieting: adding RT to caloric restriction prevents ~93.5% of the diet-induced lean-mass loss (RMD 0.819 kg [0.364-1.273], Sardeli 6-RCT MA) while leaving fat and total weight loss unchanged — RT reshapes the composition of the loss, not its total; obese-elderly only, surrogate outcomes, function not designed-for (pairs the protein lever on Protein Intake During Energy Restriction)
• Resistance Training for Sarcopenic Obesity — the sibling decision: RT alone (no diet) in older adults who already have sarcopenic obesity improves body composition (SMD 0.35, GRADE moderate) and physical function (SMD 0.36, GRADE low) but not blood biomarkers (null) over ~12 wk — the body-comp gain is fat-loss-weighted, not demonstrated muscle gain (Polo-Ferrero 9-RCT MA); a distinction from the Sardeli RT-during-deficit question, not a tension; surrogate outcomes, mostly women

Bone, joints, and fracture

• Knee Osteoarthritis and Modifiable Levers — for knee OA, which modifiable exposures reduce pain and preserve function, and how they rank (weight loss the dominant lever; appraises the risk/function levers, not the clinical management of established disease)
• Exercise Therapy for Osteoarthritis Pain and Function — the exercise lever characterized in depth (Goh gold SR+MA, 77 RCTs n=6472): exercise vs usual care gives moderate pain (SMD 0.56) and function (0.50) benefit at 8 weeks, but it decays to no-better-than-usual-care by 9-18 months unless sustained; BMI-independent (transports to the obese stratum), knee-grounded (hip benefit unestablished), determinants hypothesis-generating only
• Stationary Cycling for Knee Osteoarthritis — the exercise-MODE facet (Luan gold SR+MA, 8 cycling RCTs): cycling vs no-exercise clears MCID only on pain and sport function; and cycling is «neither superior nor inferior to other exercises» on every WOMAC/KOOS outcome — so mode is a preference/ impact-tolerance choice, not an efficacy choice, and low-impact cycling is the efficacy-equivalent default for the obese/deconditioned/injured knee (partially fills Goh’s deferred mode gap; type-F/C)
• Boswellia for Osteoarthritis — the botanical symptom-relief facet of the OA cluster (Yu gold SR-MA, 7 RCTs n=545): pain/function WMDs favour Boswellia but I2 up to 99% from product-standardization differences, small/low-quality trials, no NSAID head-to-head — a low-priority marginal adjunct, not a structural lever; specify the AKBA-standardized extract, not the shelf label
• Knee Osteoarthritis Incidence and Risk Factors — the DEVELOPING-OA counterpart (Duong gold SR+MA): which exposures raise risk of incident knee OA as route-(a) prognostic associations — obesity dominant (aOR 1.17/BMI-unit, 77% of the attributable fraction), prior injury (aOR 2.67), occupational load (the PA paradox at the knee); observational, richest on radiographic not symptomatic OA
• Vitamin D and Calcium Supplementation for Fracture Prevention — for whom supplementing vitamin D and/or calcium reduces fracture (Yao: null in the replete community-dwelling, benefit concentrated in the deficient/institutionalized), and the supplemental-calcium cardiovascular-harm signal (Bolland)
• Dairy and Bone Health — whether more milk/dairy reduces osteoporosis and hip fracture (Malmir: null once weighted by design) — the food route lands where the supplement route does, via Deficiency Repletion vs Enhancement
• Exercise for Preventing Falls in Older Adults — the falls nucleus: exercise cuts the rate of falls 23% (HIGH certainty, Cochrane 108-RCT SR); the active ingredient is balance/functional training, not volume — the better-evidenced modifiable fracture lever for the replete older adult
• Aquatic Exercise vs Land-Based Exercise for Balance in Older Adults — the modality facet (Deng gold SR+MA, 29 RCTs): water vs land is roughly a wash on balance (only overall-balance BBS survives sensitivity; dynamic-balance/walk NS; chair-stand flips null), so aquatic earns its place as a safer low-impact substitute for the joint-limited/deconditioned, not a generally superior modality
• Exercise Safety in Osteoporosis — the route-(c) contraindication facet (is exercise SAFE for fragile bone, which movements to avoid): serious harm rare/unattributable, excess is minor AEs only; avoid repetitive loaded spinal flexion, favour extension, but do not over-restrict daily bending; the safety verdict is capped by systematic UNDER-reporting of adverse events (streetlight on the harms side)
• Exercise and Bone Mineral Density — the bone-loading efficacy facet: exercise raises BMD in postmenopausal women (Mohebbi 2023, gold updated SR-MA; SMD ~0.29-0.41, moderate at best, cleanest at total hip), but BMD is a SURROGATE — the moderators (bone/menopausal status, supervision) are all null, and transmission to fewer fractures is not shown here (the falls channel, BMD-independent, carries the larger fracture signal); same-group non-independence caps confidence