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The Effects of High-Intensity Functional Training Compared with Traditional Strength or Endurance Training on Physical Performance in Adolescents: A Randomized Controlled Trial

Gavanda, Simon; Isenmann, Eduard; Geisler, Stephan; Faigenbaum, Avery; Zinner, Christoph

Journal of Strength and Conditioning Research: March 2022 - Volume 36 - Issue 3 - p 624-632doi: 10.1519/JSC.0000000000004221


Compare the effects of high intensity fitness training (HIFT) with strength training-only (ST) and endurance training-only (ET) in adolescents.

Groups trained twice a week for 6 weeks at 60 to 75 minutes per session.

Pre-and post-testing was conducted on 1) countermovement jump (CMJ), 2) 20-m sprint (20 m), 3) 3-repetition maximum back squat (3RM), and 4) the endurance Yo-Yo test.

HIFT group:

3 different workout protocols were used:

  1. Rounds for time.

  2. As many rounds possible in a given time.

  3. Performing several exercises at high repetitions in predefined order.

All workouts were completed in 5 and 20 minutes.

Exercise used were bodyweight exercises and training devices (e.g., medicine balls, plyometric boxes, skipping ropes, rings, etc.).

Initial workouts were shorter with fewer repetitions, but the goal was to exert high intensity effort.

Over the subsequent weeks both intensity and volume increased.

ST group:

Five barbell exercises: back squats, forward lunges, bent-over row, bench press, and landmine rotation.

Weeks 1 – 3 @ 3 sets of 12 reps and weeks 4 – 6 @ 3 x 8.

ET group:

Running technique focus using a speed ladder and 50- to 200-m runs @ 58% of the total training time the first week, followed by 15 minutes of long, slow distance (LDS) running. Over subsequent weeks the running technique emphasis decreased and LSD time increased. The final week consisted of only LSD for 50-60 minutes.


The HIFT group:

CMJ @ +28.5 ± 27.6%.

20-m time @ −3.9 ± 5.0%.

3RM @ +34.3 ± 23.3%.

Yo-Yo @ +14.5 ± 15.2%.

The ST group:

CMJ @ +38.3 ± 27.7%.

3RM @ +22.2 ± 11.2%.

Yo-Yo @ +12.2 ± 21.4%.

The ET group:

CMJ @ +23.4 ± 29.9%.

20-m time @ -5.2 ± 4.6%.

Yo-Yo @ +30.7 ± 37.3%.

No significant differences were found regarding sex between the groups.

HIFT is an effective training method for eliciting multifaceted improvements in strength, power, and endurance measures as compared with ET or ST alone in untrained adolescents.


The proven Specificity of Training law still the rules:

  • Training for strength-only will improve strength-related abilities.

  • Training for endurance-only will improve endurance-related abilities

  • Training with a combination of both strength and endurance (HIFT) will improve both to a degree.

  • Any type of training will improve any component of fitness by virtue of “doing something” as opposed to “doing nothing.”

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