M5 Resistance Training in Older Adults

Canadian 24 Movement Guidelines

highlights muscle strengthening activities using major muscle groups at least 2x / week

muscle and aging

data suggests muscle quantity + quality dec w/ age

muscle quantity

refers to the amount or mass of skeletal muscle in the body

sarcopenia

age-related loss of both muscle mass and strength

• often considered the primary cause of dynapenia, but the two can exist independently

muscle quality

refers to how well muscle tissue functions

• including cellular, metabolic, and mechanical properties

dynapenia

age-related loss of muscle strength

muscle quantity and quality

changes to both will be reflected in changes to muscle function

D’Onofrio et al 2023

musculoskeletal system plays a vital role in maintaining mobility, independence, and metabolic health throughout life

• primary aging

• secondary aging

primary aging

refers to the natural, inevitable biological decline that occurs with time

• intrinsic physiological changes

secondary aging

the acceleration or worsening of primary aging due to external factors, such as:

• chronic disease (e.g. diabetes, CVD, OA)

• sedentary life style or poor nutrition

• environmental stressors (e.g. pollution, inadequate recovery)

D’Onofrio et al figure

shows that both musculoskeletal and circulatory (some respiratory) may be affected by dec in muscle mass/quality

D’Onofrio et al findings

musculoskeletal mass may be maintained and disease prevented through regular PA

• untrained individuals showed more adipose tissue and less lean muscle mass

resistance training in older age

many benefits to resistance training in older age

• reduce joint pain, blood pressure, risk of falling, body fat

• improves muscle strength/mass, basal metabolic rate, bone density, glycemic control, lipid profiles, endothelial function, cognitive funciton, mental well-being

Fiatarone et al 1994

examined whether progressive resistance training and nutritional supplementation could improve muscle strength, size, and functional performance in frail elderly adults (mean age ≈ 87 years)

• Goal: Determine if even very old, frail individuals can benefit from exercise interventions

Fiatarone et al methods

Design: 10-week randomized controlled trial.

Participants: 100 frail nursing home residents (aged 72–98).

Groups:

1. Exercise + Supplement

2. Exercise only

3. Supplement only

4. Control (no intervention)

Exercise Intervention:

• Supervised progressive resistance training (high intensity) for lower limbs — primarily knee extensors.

• 3 sessions per week.

Nutritional Supplement:

• 360 kcal/day (protein-energy drink)

Fiatarone et al findings

exercise groups increased muscle strength by ~100%

• combined exercise + supplement group had similar gains to exercise alone (no strong additive effect)

Fiatarone et al outcome assessment

as part of the outcome assessment, participants wore electronic activity monitors (attached at the ankle) to objectively measure daily physical activity levels.

• done to determine whether improvements in strength and mobility translated into increased spontaneous physical activity during daily life

• exercise groups showed significant inc in daily PA

  • in contrast, control and supplement-only groups showed no significant change in activity levels

Fiatarone et al other findings

• Subjects with the lowest baseline strength but higher whole-body potassium (K⁺) — an indicator of muscle cell mass — showed the greatest relative strength increases, suggesting they still had viable muscle tissue responsive to training.

• Gait speed and stair-climbing performance both improved significantly in the exercise groups.

• Spontaneous daily physical activity (measured by ankle monitors) increased among exercisers, showing that functional gains translated to real-world movement.

• Muscle strength increased by over 100%, while muscle mass increased by only ~1.7%, indicating that most early improvements were due to enhanced neural activation and motor unit recruitment, not just hypertrophy.

Coetsee and Terblanche 2015

examined how muscle strength, endurance, and functional mobility change during a 16-week resistance training (RT) program in inactive older adults

• Goal: Determine how quickly these improvements develop and how much is lost after 16 weeks of detraining (no training)

Coetsee and Terblanche methods

Design:

• Randomized controlled trial with repeated measures.

• Duration: 16 weeks of resistance training followed by 16 weeks of detraining.

Participants:

• 41 inactive older adults (aged 55–75 years).

• Randomly assigned to:

  • RT group (n = 22)

  • Control group (n = 19)

Resistance Training Intervention:

• Supervised, full-body resistance exercises.

• 3 sessions per week, progressive intensity.

• Exercises included both upper- and lower-body movements (e.g., leg press, bench press).

Measurements:

• Muscle strength: 10RM leg press and bench press

• Functional mobility: Timed-Up-and-Go (TUG) test

• Submaximal endurance: Bruce treadmill test (time to fatigue)

• Testing every 4 weeks during RT and after 16 weeks of detraining

Coetsee and Terblanche findings

During Training (16 Weeks):

• Muscle Strength:

  • Significant increases in both upper- and lower-body strength (P < 0.001).

  • Gains appeared as early as 4 weeks and continued throughout training.

  • Average increase:

    • Leg press: +86.6 ± 44.4 kg

    • Bench press: +7.3 ± 4.9 kg

• Functional Mobility (TUG):

  • Improved only after 16 weeks (−0.2 ± 0.4 s, P < 0.05).

• Submaximal Endurance:

  • Increased after 16 weeks (+0.7 ± 0.9 min, P < 0.001).

After Detraining (16 Weeks):

• Strength: Decreased but remained above baseline (partial retention).

• Endurance: Also partially maintained.

• Functional Mobility: Fully returned to baseline (no retention).

• Control Group: No significant changes in any variable.

Coetsee and Terblanche discussion

discussion

• Strength adaptations occur rapidly and are largely maintained for some time even after stopping training.

• Mobility improvements are more transient, requiring ongoing training to sustain.

• Endurance capacity showed moderate retention, suggesting cardiovascular benefits also persist to a degree.

• Resistance training should be a core element of healthy aging programs to preserve strength, function, and independence.

Coetsee and Terblanche plateau

a plateau in strength (change in weight) between weeks 8 and 12

• first 4-8 weeks: most strength improvements come from neural adaptations — better motor unit recruitment, coordination, and firing frequency

• around 8-12 weeks: neural adaptations start to plateau, and further gains depend more on muscle hypertrophy (growth), which develops more slowly — especially in older adults

Hartman et al 2007

evaluated the effect of a long-term (26-week) heavy resistance training programme on metabolic economy (oxygen cost, respiratory exchange ratio, heart rate, perceived exertion) during functional tasks that mimic everyday activities in older adults

• Goal: determine whether resistance training not only improves strength/mass, but also makes everyday tasks “easier” (less metabolic cost) for older adults

Hartman et al methods

Design: 26-week supervised progressive resistance training intervention.

Participants: 29 older adults (mean age ≈ 66.7 years).

Intervention:

• Frequency: 3 sessions per week.

• Protocol: 2 sets × 10 repetitions per exercise.

• Intensity: Progressed from 65–70% of 1-repetition maximum (1RM).

• Exercises: Major muscle groups using resistance machines.

Measurements:

• Functional performance: walking, carrying while walking, and stair climbing tasks.

• Indirect calorimetry: oxygen uptake (VO₂), minute ventilation (V̇E), and respiratory exchange ratio (RER).

• Rating of Perceived Exertion (RPE).

Hartman et al findings

• Strength and fat-free mass: both increased significantly (p ≤ 0.001). PubMed

• Metabolic economy:

  • Oxygen cost decreased significantly by ~6% (p ≤ 0.05) for the carrying task (CAR)

  • Respiratory exchange ratio (RER) decreased significantly for walking (WLK) from ~0.84 to ~0.81 and for the stair task (STR) ~0.87 to ~0.83 (p ≤ 0.05)

  • Heart rate decreased significantly (p ≤ 0.05) only for the carrying task (CAR)

  • Perceived exertion (RPE) decreased significantly for all three functional tasks post-training

Hartman et al discussion

• Muscle Strength: Significant increases in upper and lower body strength after 26 weeks.

• Metabolic Economy: Oxygen cost (VO₂) during walking and stair climbing decreased, indicating improved efficiency.

• Functional Performance: Participants performed daily tasks with less effort and lower perceived exertion (RPE).

• Cardiorespiratory Response: V̇E and RER were lower during tasks post-training, suggesting enhanced metabolic efficiency.

Hartman et al conclusion

• Multi-joint exercises recommended:

  • Exercises that involve multiple muscle groups (e.g., leg press, chest press) are most effective for improving overall functional performance and strength in older adults.

• Increases in Fat-Free Mass (FFM) and decreases in Fat Mass (FM):

  • RT often leads to muscle hypertrophy (↑ FFM) and body fat reduction (↓ FM).

  • Even when changes in body composition are modest, strength gains are typically larger than FFM gains, reflecting neural and muscular adaptations.

• Improved economy of functional tasks:

  • Tasks like walking, stair climbing, or carrying objects become less metabolically demanding post-RT (lower VO₂, V̇E, RER).

• Reduced Rating of Perceived Exertion (RPE):

  • Participants report less effort when performing daily tasks after RT, which may make them more likely to engage in spontaneous physical activity

frailty

A multifactorial condition marked by reduced physiological reserve and sometimes cognitive decline, increasing vulnerability to adverse health outcomes (falls, disability, hospitalization)

frailty syndrome criteria

(≥3 of the following):

1. Decreased grip strength – weakness indicative of reduced muscle function.

2. Self-reported exhaustion – fatigue limiting daily activity.

3. Unintentional weight loss – >4.5 kg over the past year.

4. Slow walking speed – impaired mobility and gait.

5. Low levels of physical activity – sedentary lifestyle contributing to functional decline

exercise to challenge frailty

• Resistance training, balance, and functional task-specific exercises can counteract the physical components of frailty, improving strength, mobility, and overall independence.

• Interventions should be individualized to address the multifactorial nature of frailty, targeting muscle weakness, endurance, and functional performance.

muscle power

muscle power = force (strength) * velocity

strength power balance scale

• One side: Strength training → increases maximal force muscles can produce.

• Other side: Power training → increases force production at higher velocities.

• Both sides “balance” on function, meaning both strength and power contribute to functional ability

need both sufficient strength and the ability to produce force quickly (power) to perform functional tasks efficiently, especially in older adults

function

These are typical functional outcomes used in research or clinical settings:

• Activities of Daily Living (ADL) → e.g., dressing, bathing, carrying groceries

• Walking speed → mobility and gait efficiency

• Climbing stairs → lower-body strength & power

• Chair stands → lower-body strength and explosive power

• Balance tests → static/dynamic stability

• Rising from the floor → combination of strength, power, and coordination

having an optimal balance in strength and power will result in optimal functional outcomes

Katsoulis and Amara 2023

Goal: examine how varying frequencies of low-intensity power training (PT) affect muscle power and functional performance in healthy older women

Katsoulis and Amara methods

• Design: 12-week randomized controlled trial.

• Participants: 63 healthy women (mean age 74 ± 4 years).

• Groups:

  • PT1: 1 session/week (n = 14)

  • PT2: 2 sessions/week (n = 17)

  • PT3: 3 sessions/week (n = 17)

  • Control: No intervention (n = 15)

• Intervention:
  Low-intensity PT at 40% of 1RM, focusing on explosive concentric movements.

• Measures:

  • Leg press 1RM

  • Knee extension power (KEP)

  • Functional performance: stair climb power, stair climb time, 30-second chair stands, 400-m walk, Short Physical Performance Battery (SPPB)

Katsoulis and Amara results

• Leg Press 1RM:
  All PT groups showed significant improvements (20–33%, p < 0.05).

• Knee Extension Power (KEP):
  PT2 and PT3 groups improved by 10% and 12%, respectively.

• Functional Performance:

  • All PT groups improved in 30-second chair stands and SPPB (6–22%).

  • PT1 and PT3 improved in 400-m walk.

  • PT2 improved in stair climb power and stair climb time (4–7%, p < 0.05).

• Between-group comparison:

  • No significant differences in muscle power (KEP) or functional performance between PT1, PT2, and PT3 after 12 weeks.

  • → Increasing frequency from 1→2→3 sessions/week did not produce significantly greater outcomes.

• Within-group comparison:

  • KEP improved significantly after PT2 and PT3 compared to baseline.

  • PT1 also improved KEP, but the improvement was smaller (not always statistically significant).

• Functional performance:

  • All training frequencies (PT1, PT2, PT3) led to significant improvements in multiple functional measures compared to baseline (e.g., chair stands, stair climb, 400-m walk, SPPB).

Katsoulis and Amara discussion

• Low-intensity PT is effective in enhancing muscle power and functional performance in older women.

• The study suggests that training frequency does not significantly impact the magnitude of improvements (power or functional performance).

Katsoulis and Amara RPE

data is not consistent but for a number of tests, RPE went down for the same task (often performed at a higher level!) after training

• no change in RPE for any task for the CONTROL

Katsoulis and Amara conclusion

even w/ low intensity power training and low frequencies, there can still be meaningful improvements in power and functional performance

RT and older adults

• Strength and Power Gains:

  • Improvements in strength and power can be achieved at any age.

  • Significant strength/power gains can occur even with modest increases in muscle mass.

• Functional Performance & Fatigue:

  • RT can reduce perceived effort (RPE) during common functional tasks (e.g., walking, stair climbing, chair stands).

  • RT improves functional capacity, helping older adults perform daily activities more efficiently.

• Power Training:

  • Emerging evidence suggests power training may be especially effective for improving function.

  • Lighter intensity power training appears as effective as heavier intensity for enhancing functional performance, making it safer and more accessible for older adults.

Lavin et al 2019

Purpose:
To investigate the molecular mechanisms underlying resistance training (RT)-induced muscle hypertrophy, focusing on transcriptional networks and their variability among individuals.

• Goal:
  Determine how gene expression profiles before and after RT influence muscle growth, particularly in the absence of significant changes in muscle mass.

Lavin et al results

• Gene Expression Networks:
  Identified transcriptional networks that are predictive of hypertrophy, responsive to RT independent of muscle hypertrophy, or plastic with hypertrophy.

• Variability in Response:
  Found significant interindividual variability in gene expression profiles, suggesting that baseline muscle gene expression may contribute more to hypertrophy outcomes than RT-induced changes.

• Hypertrophy Without Mass Gain:
  Observed that some individuals experienced strength gains without corresponding increases in muscle mass, indicating that factors beyond muscle size contribute to strength improvements.

Lavin et al discussion

• Molecular Underpinnings:
  The study highlights the complexity of muscle adaptation to resistance training, emphasizing the role of gene expression in determining hypertrophic responses.

• Individual Differences:
  Acknowledges the heterogeneity in responses to RT, suggesting that personalized approaches may be necessary to optimize training outcomes.

• Strength Gains Without Hypertrophy:
  Supports the notion that neural adaptations and other factors can lead to strength improvements independent of muscle mass changes.