Multimodal HIIT Lifted Estimated VO2max 10.9% in Small Adolescent Basketball Trial

A six-week randomized trial in adolescent basketball players pitted three conditioning formats against each other and tracked aerobic capacity, sprint times and fatigue resistance. The mixed format won on all three, and the margins were not subtle.

Aerobic capacity is the quality youth coaches argue about most, because the training time available to build it is always shorter than the skill work competing for it. A randomized controlled trial published on September 19, 2026 in BMC Sports Science, Medicine and Rehabilitation tested three ways of spending that time in 36 male adolescent basketball players.

The work came from Hossein Mohit and Maryam Koushkie Jahromi of the Department of Sports Sciences at Shiraz University in Iran. Players, with a mean age of 14.8 years, were randomly assigned to multimodal high-intensity interval training, small-sided games or drill-based high-intensity interval training. Thirty of the 36 completed the program.

The intervention ran for six weeks, 12 sessions in all, twice a week. Testing covered aerobic capacity using the Yo-Yo Intermittent Recovery Test Level 1, sprint performance over 10 and 20 metres, repeated-sprint ability, agility by T-test and line drill, vertical jump by countermovement jump, and technical skills including shooting and ball control.

The multimodal group posted the largest improvements across the endurance and speed measures: estimated VO2max rose 10.9 percent, 20-metre sprint time fell 5.1 percent, and the repeated-sprint fatigue index improved by 7.39 points.

What the Six-Week Trial Compared

The three arms represent three real coaching philosophies. Drill-based intervals keep the ball in the session but structure the work around repeatable patterns. Small-sided games chase fitness through play, on the theory that game-like chaos trains the qualities a game demands. Multimodal intervals mix movement patterns and stimuli inside a single interval block.

The authors set the problem up plainly in their background: traditional interval training often lacks sport specificity, while small-sided games may fail to isolate specific physiological qualities. Each approach, in other words, trades something away. The trial asked which trade produced the most aerobic capacity per session.

Where the Aerobic Capacity Gains Landed

Estimated VO2max in the multimodal group improved by 10.9 percent over the six weeks, with a reported effect size of 2.33. That is a large figure for such a short block, and it is the number that carries the headline. It is also an estimate derived from the Yo-Yo test rather than a direct laboratory measurement.

What makes the aerobic capacity result interesting is not the raw percentage but the comparison. The multimodal group improved significantly more than the small-sided games group at p below 0.05, and more than the drill-based group at p below 0.01. Both comparison arms trained too; they simply gained less.

Sprint Times and Fatigue Resistance Followed

The endurance result did not come at the expense of speed. Twenty-metre sprint time fell by 5.1 percent in the multimodal group, with an effect size of minus 1.92, and repeated-sprint fatigue resistance improved by 7.39 points on the decrement score, effect size minus 2.66.

That combination is the practically useful part. Basketball is not an endurance sport in the marathon sense; it is a sport of repeated short efforts with incomplete recovery, so a format that raises aerobic capacity while also protecting sprint output is addressing the demand as it actually appears on the floor.

The Measures That Did Not Make the Headline

The trial tested more than endurance and straight-line speed. Agility was assessed with a T-test and a line drill, lower-body power with a countermovement jump, and technical skill with shooting and ball-control tasks. Those measures sat alongside aerobic capacity in the same testing battery, before and after the block.

The published summary reports the between-group advantages for aerobic capacity, linear sprint performance and fatigue resistance, and singles out those three as the places where multimodal work separated itself from the other formats. Readers should not assume the same separation held for jumping or for shooting, because the summary does not claim it.

That distinction matters when a trial is translated into a practice plan. A format that wins on conditioning outcomes has earned the conditioning slot, not the whole session, and skill work still has to be coached somewhere.

Why Sport-Specific Work Is Not Automatically Better

Coaches often assume the most game-like drill is the most effective one. This trial complicates that assumption. Small-sided games are maximally specific, yet they produced smaller gains in aerobic capacity than a format designed around physiological stimulus rather than game realism.

The likely reason is dose control. In a game, intensity is negotiated between players, and the athlete who most needs the stimulus is often the one who finds ways to rest. A structured interval removes that negotiation. Similar tension appears in the wider literature on sprint interval training and explosive performance in trained athletes, where prescribed work periods tend to beat free play on measurable outputs.

What a Small Trial Can and Cannot Settle

Thirty completed participants is a small sample, and the effect sizes reported here are unusually large for a six-week intervention. Large effects in small samples deserve caution as a general rule, because a handful of strong responders can move a group mean a long way.

Age is the second consideration. Adolescents are developing, and part of any improvement across six weeks in a 14-year-old cohort reflects growth and maturation alongside training. That is a known difficulty in youth research, and it runs through work such as the recent review of resistance training and muscle growth in young people, which found modest effects once the evidence was pooled.

How to Read the Aerobic Capacity Result as a Coach

The honest summary is that one well-run trial in one squad moved the odds slightly in favour of structured mixed intervals for building aerobic capacity in youth basketball. It did not settle the question, and it is not a reason to delete small-sided games from a practice plan, since those sessions carry skill and decision-making value this trial did not measure.

For general, non-individualized planning, a few points follow from the design rather than from any single number.

• Structured intervals make the dose visible; games hide it, so use games for skill and intervals when a specific physiological target matters.
• Six weeks and 12 sessions was enough to move measured outcomes, which is a realistic block length for a school or club calendar.
• Youth programs should be supervised and progressed gradually, and any conditioning plan for a growing athlete belongs with a qualified coach.
• Field tests such as the Yo-Yo are useful for tracking change over time, but treat the VO2max figure they produce as an estimate.

Context helps too. Methods that raise aerobic capacity in adults, including the altitude approaches covered in our report on hypoxic training and VO2max, do not transfer automatically to adolescents, and questions about how early to specialize are contested in their own right, as the debate over early talent selection in youth sport shows. How much activity young people accumulate in organized settings at all is a separate question, one taken up in our report on what a university sports session delivers in steps and intensity.