Orthopedics · Medical Literature
Effects of uphill running on muscle strength, jumping performance, running time, and aerobic capacity outcomes in athletes and recreational adults: A systematic review and meta-analysis.
Abstract
Uphill running is widely used in athletic training to improve lower-limb strength, jumping performance, running ability, and aerobic capacity. However, randomized controlled trials (RCTs) have reported inconsistent findings, and no prior review has focused exclusively on uphill running across these domains. This systematic review and meta-analysis aimed to evaluate the effects of structured uphill running on muscle strength, jumping performance, running time, and aerobic capacity in athletes and recreationally active adults. Six databases (CINAHL, Embase, PubMed, Scopus, SPORTDiscus, Web of Science) were searched up to June 2025 for RCTs comparing uphill running with downhill, level ground, or usual training. Methodological quality was assessed using the Physiotherapy Evidence Database scale and Cochrane risk-of-bias tool. A random-effects meta-analysis was performed, with effect sizes expressed as standardized mean differences (SMDs) and 95% confidence intervals (CIs). Thirteen RCTs (2006-2023; n = 308; mean Physiotherapy Evidence Database score = 5.4) were included, with 7 contributing to quantitative synthesis. Only trials reporting isokinetic muscle strength, jumping performance, and aerobic capacity outcomes provided sufficient data for meta-analysis. Protocols commonly involved 10 to 14 uphill sprints of 30 seconds at a ~10% gradient, performed 2 to 3 times weekly over 2 to 8 weeks. Narrative synthesis showed improvements in running economy, repeated sprint ability, and aerobic outcomes such as ventilatory threshold and lactate clearance. However, meta-analysis revealed no significant effects on isokinetic knee strength (SMD = 0.09, 95% CI = -0.41 to 0.59, P = .73; I2 = 0%), jumping performance (SMD = 0.15, 95% CI = -0.39 to 0.70, P = .59; I2 = 0%), or aerobic capacity (SMD = 0.31, 95% CI = -0.11 to 0.74, P = .15; I2 = 0%). Although statistical heterogeneity was low, the overall certainty of the evidence remained low because of the limited number of trials contributing to each meta-analysis, small sample sizes, and variability in intervention protocols and comparator conditions. Uphill running may induce favorable neuromuscular and aerobic adaptations, but meta-analysis findings did not confirm significant pooled effects on knee strength, jump performance, or aerobic outcomes. Future high-quality RCTs with standardized gradients, sufficient sample sizes, and longer durations are needed.
Clinical relevance
Uphill running is a widely implemented training modality in both competitive athletes and recreationally active adults, yet prior to this review no systematic synthesis had evaluated its effects across the domains of lower-limb strength, jumping performance, running economy, and aerobic capacity simultaneously. This meta-analysis addresses a critical evidence gap by pooling data from 13 RCTs (n = 308) spanning 2006–2023, providing sports medicine clinicians and orthopedic specialists with the highest-level synthesis currently available to guide prescription of incline-based training. Given the modality's popularity in rehabilitation and performance contexts, clarifying its true efficacy is essential for evidence-based program design.
Key findings
1. Meta-analysis of isokinetic knee strength outcomes revealed no statistically significant pooled effect of uphill running versus comparators (SMD = 0.09, 95% CI = −0.41 to 0.59, P = .73; I² = 0%), indicating negligible and imprecise benefit on objective knee extensor/flexor torque. 2. Jumping performance showed no significant pooled effect (SMD = 0.15, 95% CI = −0.39 to 0.70, P = .59; I² = 0%), suggesting uphill sprint protocols do not confer a statistically detectable advantage in plyometric output over comparator conditions. 3. Aerobic capacity outcomes also failed to reach statistical significance in meta-analysis (SMD = 0.31, 95% CI = −0.11 to 0.74, P = .15; I² = 0%), though the effect size trend was moderate and the confidence interval approached clinical meaningfulness. 4. Statistical heterogeneity was uniformly low across all three pooled domains (I² = 0%), indicating consistency of individual trial results despite variability in protocols; the absence of significance therefore reflects small sample sizes and limited trial numbers rather than conflicting study outcomes. 5. Narrative synthesis of trials ineligible for meta-analysis demonstrated qualitative improvements in running economy, repeated sprint ability, ventilatory threshold, and lactate clearance, suggesting domain-specific aerobic and metabolic benefits not yet quantifiable through pooled analysis. 6. The overall body of evidence was rated low certainty, derived from only 13 RCTs with a mean PEDro score of 5.4/10, a total pooled sample of 308 participants, and heterogeneous intervention protocols (10–14 × 30-second uphill sprints at ~10% gradient, 2–3 sessions/week, over 2–8 weeks), limiting generalizability.
Practice implications
Clinicians and sports medicine specialists should not currently rely on uphill running as a standalone, evidence-confirmed intervention for improving isokinetic knee strength, jump performance, or VO₂-based aerobic capacity, as pooled meta-analytic data do not support statistically significant benefits in these domains; it may, however, serve as a complementary modality given narrative evidence of improvements in running economy, lactate clearance, and ventilatory threshold. When prescribing uphill running, the most commonly studied and tolerated protocol — 10 to 14 sprints of 30 seconds at approximately 10% gradient, two to three times per week for a minimum of 6–8 weeks — represents a reasonable starting framework for athletes and active adults, with individual titration based on fitness level and orthopedic tolerance. Future clinical decision-making should await high-quality RCTs with standardized gradient and duration protocols, adequate sample sizes, and active comparator designs before uphill running is elevated to a first-line evidence-based recommendation in strength or aerobic conditioning programs.