Actionable Data Report 081:

Muscle Strength and Gait Speed Strongly Predict Mortality Risk in Older Adults

Article Title:

Power, Strength, And Physical Function: A Prospective Study Examining All - cause Mortality

Overview:

This prospective cohort study analyzed data from over 2,600 U.S. adults aged 50+ from the National Health and Nutrition Examination Survey (NHANES, 1999–2002) to assess how lower extremity muscular strength, power, and physical function impact all-cause mortality. The study used time-to-peak force (TPFs), peak force (PF-N), and 20-foot walk time (TTCW) as core metrics, with mortality tracked via the National Death Index.

Results and Interpretation:

Key Findings:

• Higher peak force (PF-N) was associated with lower risk of death in a dose-response pattern:

  • Q2: HR 0.59

  • Q3: HR 0.48

  • Q4: HR 0.32 (vs. lowest strength quartile, Q1)

• Faster 20-foot walk times (TTCWs) also predicted lower mortality:

  • Q1 (fastest walkers): HR 0.35

  • Q2: HR 0.58

  • Q3: HR 0.64 (vs. Q4, slowest)

• Time-to-peak force (TPFs) had no significant association with mortality.

• Associations were adjusted for comorbidities, demographics, and waist circumference—confirming independence of strength and gait speed as predictors.

Actionable Data Steps

To implement these findings effectively within tactical populations, consider the following recommendations:

1. Test and Track Peak Force and Gait Speed in Aging Adults

• Use handheld or leg dynamometers to test peak force.

• Use a 20-foot timed walk test for a quick, field-based measure of mobility and mortality risk.

2. Program for Lower Body Strength and Speed—Not Just Endurance

• Prioritize compound lifts, stair climbs, and resisted walks in older or deconditioned populations.

• Include neuromuscular power drills (e.g., sit-to-stand speed, low box jumps) where safe and feasible.

3. Screen Beyond Vitals—Function Is a Vital Sign

• Add gait speed and force testing to yearly functional assessments.

• Use mobility and leg strength metrics to triage fall risk, hospitalization likelihood, and care intensity.

Why This Matters:

This study reinforces the now well-established truth: gait speed and leg strength are survival metrics. If an older adult can't produce force or move quickly, they're on a faster track to poor health outcomes—regardless of medical diagnoses. Tactical aging means monitoring what moves the system, not just what’s in the bloodwork.

Definitions:

• PF-N (Peak Force – Newtons): Maximal force output from lower extremities

• TTCW (Time to Complete Walk): Speed over a 20-foot distance

• HR (Hazard Ratio): Relative risk of mortality across performance quartiles

Further Learning:

• Investigate how combined upper + lower body strength impacts mortality

• Study how different training modalities (e.g., resistance bands vs. free weights) affect long-term outcomes

• Explore power training adaptations in adults aged 70+

Reference:

Boyer, William & Williams, Charles & Churilla, James. (2022). Power, Strength, And Physical Function: A Prospective Study Examining All-cause Mortality. Medicine & Science in Sports & Exercise. 54. 571-571. 10.1249/01.mss.0000882224.16966.d6.

Actionable Data Report 076:

Actionable Data Brief: Handgrip Strength Predicts Longevity—Relative Strength Matters More

Article Overview:

This longitudinal cohort study from the Korean Longitudinal Study of Aging (KLoSA) followed 9,102 participants over 13 years to examine how absolute and relative hand grip strength (HGS) impact all-cause mortality. Both forms of strength were tested for their predictive value, adjusting for chronic diseases, cognitive function, depression scores, and lifestyle factors.

Results and Interpretation:

Key Findings:

• Absolute HGS:

  • Each 1 kg increase = 3.2% lower risk of all-cause mortality (Adjusted HR = 0.968, 95% CI: 0.958–0.978).

• Relative HGS (grip strength/BMI):

  • Each 1 kg/BMI increase = 22% lower risk of all-cause mortality (Adjusted HR = 0.780, 95% CI: 0.634–0.960).

• Subgroup Insights:

  • High HGS was protective in both men and women, and in both <65 and ≥65 age groups.

  • Relative HGS was an even stronger mortality predictor among those with more than two chronic diseases.

• Clinical Relevance:

  • Grip strength remained a strong independent predictor even after adjusting for cognitive decline, depression, and multimorbidity.

Actionable Data Steps:

1. Integrate HGS Testing Into Routine Health Screening

• Use dynamometers in annual check-ups for adults aged 45+.

• Record both absolute values (kg) and relative values (kg/BMI).

2. Prioritize Strength Training in At-Risk Groups

• Especially focus on middle-aged adults, those with multiple chronic diseases, and the elderly.

• Emphasize resistance training, protein optimization, and multimodal programs targeting neuromuscular function.

3. Use HGS as a Mortality Risk Stratifier

• Low HGS = higher priority for preventive interventions (nutrition, physical activity, fall prevention).

• Monitor HGS alongside BMI, MMSE, and CES-D scores for holistic risk profiling.

Why This Matters:

Handgrip strength isn’t just about musculoskeletal health—it’s a global survival marker. Improving or maintaining strength, especially relative to body size, could extend life expectancy and reduce the burden of chronic disease. Tactical aging means keeping strength at the forefront, not as an afterthought.

Definitions:

• Absolute HGS: Total force output measured directly in kg.

• Relative HGS: Force output normalized to BMI (kg/BMI).

• CES-D: Depression score screening tool; MMSE: Cognitive function score.

Further Learning:

• Research long-term strength-building interventions in populations with low baseline HGS.

• Investigate HGS predictive power for cause-specific mortality (e.g., cancer, CVD, falls).

• Test wearable tech or grip-based devices for real-time strength monitoring.

Citation:

Jeong W, Moon JY, Kim JH. Association of absolute and relative hand grip strength with all-cause mortality among middle-aged and old-aged people. BMC Geriatr. 2023;23(1):321. Published 2023 May 23. doi:10.1186/s12877-023-04008-8