Mixed session periodization as a new approach for strength, power, functional performance, and body composition enhancement in aging adults

Key points

1. 01Both MSP and TP significantly increased lower-limb and upper-body strength versus a non-training control group, with no statistically significant difference between the two training groups.
2. 02MSP produced larger effect sizes than TP for leg press (ES 3.38 vs 2.56), seated leg curl (ES 2.27 vs 1.53), lower-limb fat-free mass (ES 0.26 vs 0.09), and all three functional tests.
3. 03Both groups improved stair-climbing and timed-up-and-go performance; MSP showed a small effect size (0.50-0.58) while TP showed only trivial effects (0.21-0.43) for these tasks.
4. 04Countermovement jump height increased significantly at week 7 for both groups versus baseline (p = 0.001), suggesting early power adaptations.
5. 05A 33% dropout rate and small final sample (n = 30) limited statistical power, meaning real between-group differences may have been missed.

How it was conducted

Design

Randomized controlled trial with three parallel groups and repeated measures at baseline, week 7, week 11, and week 15

Participants

30 healthy untrained adults aged 56-76 years (17 men, 13 women) who completed the protocol; 45 originally randomized (33% dropout)

Groups

Mixed-session periodization (MSP, n=11), traditional block periodization (TP, n=11), and non-training control (CG, n=8)

Intervention

9 weeks of resistance training, 3 sessions per week (~37 minutes per session); TP used sequential mesocycles (hypertrophy then strength then power); MSP combined all three methods within every session

Primary outcomes

5RM leg press and seated leg curl, 12RM cable chest press, countermovement jump and squat jump height and peak power output, timed up and go, stair ascent and descent time, lower-limb body composition by DXA

What they found

• Leg press 5RM absolute strength: MSP increased from 108.81 +/- 25.11 kg to 138.54 +/- 28.41 kg (ES = 3.38, large); TP increased from 96.72 +/- 28.66 kg to 122.27 +/- 36.60 kg (ES = 2.56, large); both significantly greater than control at week 15 (p < 0.0001).
• Seated leg curl 5RM: MSP increased from 75.63 +/- 17.98 kg to 99.81 +/- 18.06 kg (ES = 2.27, large); TP increased from 72.54 +/- 20.91 kg to 87.54 +/- 23.07 kg (ES = 1.53, moderate); no significant difference between groups (p = 0.76).
• Cable chest press 12RM: both experimental groups significantly increased from baseline (p < 0.001 for both); control group significantly decreased (p = 0.048); group x time interaction F = 49.78, p = 0.0001.
• Countermovement jump height at week 7 was significantly greater than baseline (p = 0.001) for both training groups; MSP increase was 37% (ES = 1.45), TP increase was 26.5% (ES = 1.00).
• Functional performance at week 15: MSP effect sizes were small for TUG (0.50), upstairs (0.53), and downstairs (0.58); TP effect sizes were trivial for TUG (0.21) and upstairs (0.43) and trivial for downstairs (0.30); no between-group statistical differences (p > 0.05).
• Lower-limb fat-free mass: MSP gained 4.8% (ES = 0.26, p = 0.0001); TP gained 2.6% (ES = 0.096, p = 0.007); MSP was significantly greater than control (p = 0.009, ES = 2.81) but not significantly different from TP (p = 0.139).
• Rating of perceived exertion was significantly lower for MSP (8) than TP (9) (p < 0.001), despite similar absolute training volume loads (MSP: 5,007 +/- 891 kg; TP: 4,271 +/- 1,339 kg; p = 0.14).
• Bone mineral density did not differ significantly between groups at any time point for spine, femur, or lower limb (p > 0.05).

Limitations

• Small final sample size (n = 30 after 33% dropout) reduced statistical power, raising the possibility that real between-group differences were missed (type II error).
• Short 9-week intervention; untrained status of participants at baseline may have amplified responsiveness to any resistance training program, masking true differences between periodization models.
• Baseline imbalance: MSP group had significantly greater lower-limb fat-free mass than the control group (p < 0.05), which could affect body composition comparisons.
• No blinding of participants or trainers was possible, and the study was conducted in a supervised laboratory setting that may not reflect real-world adherence conditions.

Why it matters

For patients

Older adults can expect meaningful gains in leg strength, stair-climbing ability, and muscle mass from either a traditional or mixed-session weight training program over about 9 weeks.

For clinicians

Both periodization models are viable for older untrained patients; MSP may offer slightly greater functional and body composition benefits and produced lower perceived exertion, making it worth considering for this population.

For readers

This small RCT provides preliminary evidence that mixing hypertrophy, strength, and power training within a single session is at least as effective as sequential block training for aging adults, with a trend toward larger effect sizes for MSP.