Functional training vs. traditional PE: A 36‑week school study shows bigger gains in endurance, strength and movement quality among male adolescents

Table of Contents

1. Key Highlights
2. Introduction
3. Study design and the students who took part
4. What the functional training program actually required
5. How outcomes were measured and analyzed
6. Key findings after 18 weeks: early signals of difference
7. What shifted by 36 weeks: duration matters
8. Interpreting effect sizes: statistical versus practical significance
9. Why the functional program outperformed standard PE in selected domains
10. Attrition, adherence and implementation realities
11. Body composition and nutrition: why exercise alone fell short
12. Safety and ethical considerations
13. How these results compare with prior literature
14. Practical recommendations for schools and practitioners
15. Limitations that shape interpretation
16. Policy and research priorities arising from the trial
17. Translating the study into practice: example implementation roadmap
18. FAQ

Key Highlights

• A 36‑week structured, progressive functional training program produced significantly greater improvements than standard physical education in cardiorespiratory endurance, lower‑body strength and several measures of agility, balance and movement quality among 670 male high‑school students.
• Improvements were duration‑dependent: some benefits (notably lung capacity, squat 1RM and movement quality) became statistically distinct only after the full 36 weeks; attrition and lack of dietary control limit generalizability.

Introduction

High school marks a window of physiological maturation and habit formation that shapes long‑term health. Schools are uniquely positioned to influence adolescent fitness through regular, supervised activity. A multi‑school longitudinal trial in China compared a deliberately structured functional training program with traditional sport‑based physical education across 36 weeks. The trial measured 19 fitness indicators spanning body composition, cardiorespiratory function, muscular strength and endurance, flexibility, speed, coordination, agility, explosive power and balance. Findings clarify which components of adolescent fitness respond quickly to a school‑based exercise program, which require sustained exposure, and where traditional PE already delivers similar benefits.

The following report distills the trial’s methods and results, evaluates practical significance, examines limitations that affect interpretation, and outlines actionable considerations for schools, coaches and policymakers interested in implementing evidence‑based curricular change.

Study design and the students who took part

Eighteen high schools across Guizhou, Shandong and Sichuan provinces enrolled 670 male students aged 16–18 years. Participants were individually randomized within schools to a functional training group (FTG, n = 351) or a traditional physical education group (TPEG, n = 319). Inclusion criteria were deliberately narrow: visual acuity ≥4.8, height 163–185 cm and a National Student Fitness Health Standards (NSFHS) score ≥60. These exclusions produced a relatively homogeneous cohort and reduced the likelihood of adverse events during maximal strength testing, but they also restrict generalizability to wider adolescent populations (for example, females, students with lower baseline fitness or corrected vision).

Baseline characteristics were balanced across arms (mean age ~17.2 years; mean height ~174 cm; mean weight ~68 kg; NSFHS score ~76), so subsequent differences reflect the intervention rather than pre‑existing imbalance.

Randomization used a computer sequence with allocation concealment; instructors were trained and sessions were scheduled separately to minimize contamination. Assessors were blinded to group allocation for testing. Testing followed standardized protocols with high inter‑rater and test–retest reliability (ICC > 0.85–0.95 on subsamples).

What the functional training program actually required

The intervention was a structured, progressive two‑phase program delivered over 36 weeks with a total weekly exercise dose of roughly 210 minutes: two 45‑minute in‑class sessions plus two 60‑minute extracurricular sessions. The program combined circuit‑style resistance and motor control work, agility drills and small‑sided game play. Phase I (weeks 1–18) emphasized foundational motor function—stability, flexibility and motor control—using primarily bodyweight exercises at higher repetitions (12–15 reps). Phase II (weeks 19–36) increased loading and complexity with weighted vests (2–5 kg) and dumbbells (2–8 kg), lower repetition ranges (8–12 reps) and more targeted lower‑limb conditioning and core work.

Typical exercises included squats, lunges, planks, push‑ups, balance drills and agility ladder work. Intensity was monitored with RPE (target 12–15 on Borg 6–20); progression criteria were applied every 4–6 weeks. Instructors received an 8‑hour workshop and fidelity monitoring exceeded 90% on unannounced visits.

The comparison arm (TPEG) matched contact time but followed standard sport‑centered PE (basketball, volleyball, football) and common extracurricular activities (running, badminton, calisthenics), without the structured progression and load management that characterized the FTG.

How outcomes were measured and analyzed

Nineteen indicators across 11 fitness categories were measured at baseline (T1), after Phase I at 18 weeks (T2), pre‑Phase II after summer holiday (T3) and after Phase II at 36 weeks (T4). Primary analyses compared T1→T2 and T1→T4. The analytic backbone was linear mixed models (LMMs) with baseline adjustment, random intercepts for participant and school, and inclusion of age and baseline fitness as covariates. LMMs accommodate missing data under a Missing At Random assumption and the trial followed an intention‑to‑treat principle.

To address multiple testing across 19 outcomes, the False Discovery Rate (Benjamini–Hochberg) correction was applied. Secondary analyses included t‑tests and repeated measures ANOVA for comparison with prior studies. Prespecified primary outcomes were the 1000‑m run (cardiorespiratory) and 1RM squat (muscular strength).

Attrition was substantial: completion at 36 weeks was 53.3% in FTG (n = 187) and 62.7% in TPEG (n = 200), with overall Phase II attrition of 46.7% and 37.3% respectively. Dropout was associated with allocation to FTG (OR = 1.62, p = 0.006) and lower baseline NSFHS score. Reasons included illness, relocation and loss of motivation. Multiple imputation sensitivity analyses produced broadly consistent results with the primary LMMs.

Key findings after 18 weeks: early signals of difference

After the first 18 weeks, FTG already showed advantages on several indicators:

• Cardiovascular: Resting pulse decreased in FTG compared with an increase in TPEG (t‑test p = 0.018; standardized effect d = 0.19).
• 1,000‑m run: FTG improved by ~10.11 s while TPEG worsened by ~5.24 s (p < 0.001; d = 0.53).
• Muscular strength: 1RM squat increased in FTG (+1.78 kg) versus a decrease in TPEG (−4.60 kg) (p < 0.001; d = 0.30). Pull‑ups rose in FTG (+0.27 reps) and declined in TPEG (−0.88 reps) (p = 0.001; d = 0.27).
• Agility and balance: FTG showed attenuated declines in 50‑m run and T‑test times relative to TPEG (both p < 0.03), and a smaller decline in closed‑eye single‑leg stance (p < 0.001; d = 0.32).

Several domains did not differ at 18 weeks: body composition, many measures of muscular endurance, sit‑and‑reach flexibility and FMS pattern scores. Those measures either require longer exposure or complementary interventions (for example, dietary modification for body composition).

What shifted by 36 weeks: duration matters

The full academic year amplified several effects and revealed domain‑specific timing of adaptation.

Prominent 36‑week differences favoring FTG included:

• Muscular strength and endurance: 1RM squat showed a large FTG advantage (Δ FTG +17.20 kg vs. TPEG −6.31 kg; p < 0.001; d = 0.66). The eight‑level abdominal bridge favored FTG (+19.89 vs. +9.96; p < 0.001; d = 0.89), representing one of the largest effects in the study.
• Cardiorespiratory function: resting pulse (p = 0.001; d = 0.34) and lung capacity (+265 mL vs. −12 mL; p < 0.001; d = 0.36) improved more in FTG. The 1000‑m run still favored FTG (p = 0.016; d = 0.24).
• Movement quality and skill‑related fitness: FMS trunk stability, hurdle steps and rotational stability showed significant between‑group differences only at 36 weeks (p = 0.026, 0.012, 0.040 respectively). T‑test agility and closed‑eye single‑leg balance also favored FTG.
• Flexibility: sit‑and‑reach performance improved in FTG relative to TPEG (p = 0.001; d = 0.35).

Despite these gains, several outcomes did not show lasting between‑group differences. Pull‑ups were significant at 18 weeks but not at 36 weeks; maximum bodyweight squat repetitions and standing long jump did not differ significantly at 36 weeks. Body composition measures (BMI, body fat percentage, waist:hip) showed limited between‑group separation at individual time points, though ANOVA detected time×group interactions for BMI and body fat percentage.

Formal LMM contrasts confirmed duration‑dependent effects: the FTG–TPEG difference was significantly larger at 36 weeks than at 18 weeks for lung capacity, 1RM squat and closed‑eye single‑leg stance.

Interpreting effect sizes: statistical versus practical significance

Effect sizes ranged from small to large. The largest standardized effects were seen for lower‑body strength and core endurance (1RM squat d ≈ 0.45 in LMMs and d ≈ 0.66 in t‑test secondary analyses; eight‑level abdominal bridge d ≈ 0.89). These magnitudes indicate meaningful physiological change in muscular capacity over a school year with progressive overload.

Cardiorespiratory indicators produced small to moderate effects: the 1,000‑m run had a substantial LMM d = 0.53 at 18 weeks and a smaller d = 0.24 at 36 weeks in secondary tests. Resting pulse and lung capacity effects were small‑to‑moderate (d ≈ 0.24–0.36). Small effect sizes (d ≈ 0.18–0.30) on measures such as 50‑m run or T‑test still matter at population scale: marginal improvements in adolescents can translate into reduced cardiometabolic risk when scaled across school systems.

Movement quality indicators showed small effects (d ≈ 0.21–0.26). These outcomes are clinically meaningful for injury risk reduction and long‑term motor competence, though they require prolonged exposure to structured training to shift.

Body composition had negligible standardized effects (d ≈ 0.03–0.07), underlining a recurrent finding: exercise alone—at least at the intensity and population studied—yields modest changes in adiposity without concurrent dietary intervention or in populations that are not overweight at baseline.

Why the functional program outperformed standard PE in selected domains

Several mechanistic and programmatic elements explain the pattern of results:

• Progressive overload and specificity: The FTG introduced systematic progression (volume, load, complexity) with regular monitoring and individualized regressions. This approach drives neural and muscular adaptation more efficiently than unstructured sport practice.
• Multi‑component stimulus: Circuit training, unilateral and unstable variations, and core conditioning target neuromuscular control, balance and intermuscular coordination. These features translate into improved balance, agility and movement patterns.
• Dose and intensity: Although weekly contact time matched TPEG, FTG sessions intentionally elevated RPE and maintained structured intensity, particularly in Phase II with added external loads. Circuit formats often sustain elevated heart rates and metabolic demand, producing cardiorespiratory benefits even without dedicated endurance sessions.
• Supervision and instruction quality: Instructors received focused training and fidelity monitoring. Correct technique and progression criteria preserve stimulus quality, reduce compensatory movement and accelerate adaptation.
• Transfer effects: The movement competency emphasis likely improved running economy and stability, which can reduce energy cost in endurance tasks and produce better timed runs and lower resting pulse.

However, the study design does not isolate functional training alone. The intervention differed from traditional PE not only in exercise modality, but in progression, supervision and load prescription. Therefore, the observed advantages are best attributed to a structured, progressive exercise program incorporating functional elements rather than to functional training in isolation.

Attrition, adherence and implementation realities

Attrition was a major practical constraint. Completion at 36 weeks was 53.3% in FTG and 62.7% in TPEG. Reasons included illness, family relocation, time constraints and loss of motivation. FTG exhibited higher dropout early in Phase II; greater time demands and progression intensity may have reduced continued engagement for some students.

Attendance among completers averaged 82.4% (FTG) and 89.7% (TPEG); fewer FTG students achieved ≥75% adherence. Differential attrition raises the risk of bias if dropouts differed on unmeasured variables (for example, motivation or outside commitments). The trial addressed this via LMMs and multiple imputation, but informative missingness cannot be fully excluded.

Implementation fidelity was high (>90%) based on unannounced checks. This strengthens confidence that program delivery matched the protocol, and that observed effects are replicable with adequate training and oversight.

Real‑world adoption requires attention to engagement strategies: embedding progression within available school time, reducing equipment barriers, providing varied session formats, and fostering intrinsic motivation may improve retention. Incentives, peer support and integrating parental communication have improved adherence in other adolescent programs and deserve testing here.

Body composition and nutrition: why exercise alone fell short

Group‑level changes in BMI and percent body fat were minimal despite significant time×group interactions for some measures. Several factors account for this:

• Baseline characteristics: The cohort had mean BMI ~22.4 kg/m² and was not predominantly overweight. Detecting reductions in adiposity among normoweight adolescents requires larger energy deficits or targeted interventions.
• Unmonitored diet: No dietary assessment or counseling was part of the protocol. Nutritional intake is a dominant determinant of adiposity change; exercise programs without caloric/nutrient strategies often achieve limited fat loss.
• Holiday interruption: A two‑month summer break separated phases with no monitoring. Variation in activity and diet across that period likely attenuated continuous training effects on composition.
• Active comparator: TPEG also provided ~210 min/week of activity, reducing contrasts in total energy expenditure.

Schools aiming to influence body composition should couple structured exercise with nutrition education and environmental strategies (cafeteria offerings, parental engagement) and consider strategies to maintain activity in holiday periods.

Safety and ethical considerations

1RM squats were included and required safety procedures: familiarization, spotting, standardized warm‑ups and progressive loading. No withdrawals were attributed to intervention‑related injuries. The ethics committee approved passive parental consent given the research compared two standard educational approaches; written guardian consent was later recorded per institutional requirements. Despite safety safeguards, introducing maximal strength testing and higher‑intensity training in wider school contexts would require robust instructor training, screening and emergency planning.

How these results compare with prior literature

The study findings align with evidence that structured resistance and functional training improve muscular strength, movement skills and some cardiorespiratory indicators in adolescents. Earlier trials reported gains from resistance training integrated into school curricula; this study extends those findings over a full academic year and shows duration‑dependent effects for some outcomes such as lung capacity and movement quality.

The limited effects on body composition echo meta‑analytic conclusions that combined diet and exercise interventions outperform exercise‑alone programs in affecting adiposity among adolescents.

Where the present trial adds value is in simultaneous measurement across 19 indicators and the explicit contrast of 18‑ vs. 36‑week effects. The differentiated time course—early gains in cardiovascular and strength markers, later emergence of movement quality changes—clarifies expectations for educators and policymakers.

Practical recommendations for schools and practitioners

For schools considering similar programming the following points emerge from the trial:

• Plan for long duration. Several important outcomes required a full academic year to materialize. One‑term pilots should not be taken as definitive tests of efficacy.
• Emphasize progression and supervision. Structured overload with clear progression criteria and trained coaches yielded the largest strength and neuromuscular gains.
• Preserve contact dose. Both FTG and TPEG logged ~210 minutes per week; matching contact time while improving content quality appears feasible within existing timetables.
• Pair exercise with nutrition. If body composition is a primary target, integrate dietary education and environment‑level changes.
• Monitor and boost adherence. Expect attrition. Build engagement strategies—student choice, gamification of progress, parental involvement, flexible scheduling—to reduce dropout.
• Use appropriate screening. For safety with maximal strength testing and weighted implements, screen for contraindications and ensure instructor competence.
• Start inclusively. The trial excluded several student subgroups. Future implementations should adapt progressions to include students with lower baseline fitness or medical considerations, using regressions and individualized load prescriptions.

Real‑world pilots that incorporate teacher training, resource mapping, and continuous monitoring will be essential to scale such programs beyond proof‑of‑concept settings.

Limitations that shape interpretation

Several methodological and contextual limitations warrant attention when interpreting the results and considering generalization:

• Narrow inclusion criteria: Visual acuity, height range and NSFHS minimum excluded many students. Results therefore apply to a restricted male adolescent subgroup and cannot be generalized to girls, shorter/taller students, those with corrected vision or lower baseline fitness.
• Differential attrition: Higher dropout in FTG (46.7% vs. 37.3%) raises the possibility of selection bias. Although LMMs and multiple imputation were used, informative missingness cannot be excluded.
• Active comparator: TPEG offered substantial physical activity. This active control reduces the magnitude of between‑group differences compared with a no‑treatment control and reflects a pragmatic, real‑world comparison.
• Unmonitored holiday period: A two‑month summer break without monitoring introduced uncontrolled variation in physical activity and diet between phases.
• No dietary assessment: Interpreting body composition results is limited without nutritional data.
• FMS limitations: The Functional Movement Screen is intended as a screening tool rather than a validated quantitative measure of motor competence; using more sensitive instrumented or observational measures could refine interpretation of movement quality changes.
• Male‑only sample: Sex‑specific responses to training are well documented; female adolescents may respond differently.

These constraints do not invalidate the core findings but frame them as evidence for the efficacy of a structured, progressive program in a specific group under carefully monitored conditions.

Policy and research priorities arising from the trial

Evidence from the trial supports several priorities:

• Pilot year‑long structured programs within school districts with rigorous monitoring of fidelity, adherence and safety.
• Couple exercise programming with nutrition interventions when adiposity or metabolic outcomes are targets.
• Test scalable engagement strategies to reduce attrition, such as peer leadership, modular sessions, and blended digital tools for at‑home continuity during holidays.
• Expand trials to include female students and a broader range of baseline fitness and anthropometric profiles to test external validity.
• Use cluster‑randomized designs where feasible to evaluate implementation at school level and capture between‑school variation.
• Incorporate laboratory measures (VO2max, DEXA) in subsamples to validate field measures and explore physiological mechanisms.
• Investigate long‑term follow‑up to determine whether school‑based gains translate into sustained physical activity habits and health benefits into adulthood.

For policymakers, the evidence suggests that modest curricular restructuring—embedding progressive, supervised resistance and movement training into PE—can elevate muscular strength and certain cardio‑respiratory and movement outcomes beyond traditional sport‑based lessons.

Translating the study into practice: example implementation roadmap

A practical pathway for secondary schools interested in adopting a similar model:

1. Needs assessment: inventory teacher skills, equipment and schedule; survey student interest and baseline fitness.
2. Teacher training: an 8‑ to 12‑hour workshop on progression, load management, safety and RPE monitoring; produce a session manual and video resources.
3. Pilot cohort: implement with one grade cohort for a full academic year, matching weekly contact hours to existing PE allocation.
4. Fidelity checks: unannounced observations, standardized checklists and a simple digital log for session attendance and RPE.
5. Engagement strategies: use student goal‑setting, small‑group competition, and feedback on measurable strength gains to sustain motivation.
6. Evaluation: pre/post assessment of a core battery (1RM squat or scaled alternative, 1,000‑m run, balance, T‑test, sit‑and‑reach), plus process metrics (attendance, perceived exertion).
7. Scale and iterate: adapt based on pilot results, incorporate nutrition components if body composition change is a goal.

This roadmap respects school constraints while leveraging the clear elements that produced benefit in the trial: progression, supervision, and continuity.

FAQ

Q: Who were the participants and can these findings be applied to all students? A: Participants were male high‑school students aged 16–18 who met strict inclusion criteria (visual acuity ≥4.8, height 163–185 cm, NSFHS score ≥60). Results apply most directly to similar male adolescent cohorts. Female students, younger adolescents, or those with lower baseline fitness or different anthropometrics may respond differently; replication in broader samples is necessary before universal application.

Q: Did the study prove that "functional training" is better than regular PE? A: The study showed that a structured, progressive exercise program that included functional training elements produced greater improvements in several fitness domains than standard sport‑centred PE. However, the intervention differed from traditional PE in structure, progression, supervision and intensity. Benefits are therefore attributable to the structured progressive program as a whole rather than to any single component labeled “functional training.”

Q: How large were the gains and are they meaningful for student health? A: Effect sizes ranged from small to large (Cohen’s d ≈ 0.18–0.89). The largest gains appeared in lower‑body strength and core endurance—outcomes with clear implications for movement capacity and injury resilience. Small improvements in cardiorespiratory markers also matter at population scale. Practical significance depends on school goals; for strength and core function, changes were clearly meaningful.

Q: Why were body composition changes limited? A: Participants had average BMI in the normal range, and no dietary intervention accompanied the exercise program. Without controlled nutrition and in non‑overweight cohorts, exercise alone typically produces modest adiposity changes. A combined diet‑and‑exercise strategy is preferable where changes in body fat are a primary aim.

Q: The study had high dropout, especially in the intervention arm. Should schools worry? A: Differential attrition indicates engagement and workload must be carefully managed. FTG students faced higher demands from structured progression and extracurricular sessions, which likely contributed to higher dropout. Schools should pilot programs with attention to scheduling, student motivation and flexible progressions to maintain adherence.

Q: Is it safe to implement similar programs in schools? A: With appropriate screening, teacher training, safety protocols (spotting, familiarization, progressive loading) and supervision, structured resistance and movement training can be delivered safely. This trial reported no withdrawals due to intervention‑related injury. Safety infrastructure is essential when introducing maximal strength or weighted implements.

Q: How long should a school run such a program to see benefits? A: Some improvements (cardiorespiratory and strength) appeared within 18 weeks; movement quality and lung capacity differences were more evident after 36 weeks. A full academic year provides the best opportunity for durable, multi‑domain adaptation.

Q: What additional resources will a school need to run this type of program? A: Teacher training, a simple stock of small external loads (weighted vests, light dumbbells), space for circuits, monitoring tools (RPE scales, attendance logs) and a program manual. Investment in staff development and fidelity checks maximizes benefit.

Q: What should researchers study next? A: Trials that include female students, broader inclusion criteria, dietary components, laboratory measures (VO2max, DEXA), longer follow‑up and strategies to reduce attrition will strengthen the evidence base. Cluster‑randomized designs to assess implementation at school level are also a priority.

Q: If a school has limited equipment, can this be done? A: Yes. Phase I of the program used bodyweight exercises and produced early gains. Phase II included small external loads to accelerate strength adaptation, but regressions and bodyweight‑progressions can serve schools with minimal equipment.

Q: Are the findings relevant outside China? A: The physiological principles of progressive overload, motor control and neuromuscular adaptation are generalizable. However, cultural, curricular and resource differences affect implementation and engagement. Local piloting with contextual adaptation is recommended.

Q: Who should lead implementation at school level? A: Physical education teachers with additional training in resistance programming and motor control should lead; partnerships with local university exercise science departments or certified strength coaches can support teacher training and fidelity monitoring.

Q: What are the main takeaways for school leaders? A: Structured, progressive exercise programs embedded in the school year can improve adolescents’ muscular strength, some cardiorespiratory markers and movement quality more than traditional sport‑based PE. Expect greater returns with sustained implementation, invest in teacher training, and pair exercise with nutrition and engagement strategies when broader health outcomes are sought.