Muscle Recovery after a Single Bout of Functional Fitness Training

Abstract

Background: Functional fitness training (FFT) is a new exercise modality that targets functional multi-joint actions via both muscle-strengthening exercises and aerobic training intervals. The aim of the study was to examine muscle recovery over a 20 min period after an FFT workout in trained adults. Materials and methods: Participants were 28 healthy trained subjects. In a single session, a countermovement jump (CMJ) was performed to determine several mechanical variables (jump height, maximum velocity, power) before (preFFT) and 4, 10, and 20 min after the FFT workout (postFFT). In parallel, capillary blood lactate concentrations were measured pre- and 3 min postFFT. Heart rate was also measured before and after the workout, and perceived exertion was measured postFFT. Results: Significant differences between the time points preFFT and 4 min and 10 min postFFT, respectively, were produced in jump height (p = 0.022, p = 0.034), maximum velocity (p = 0.016, p = 0.005), average power relative (p = 0.018, p = 0.049), and average power total (p = 0.025, p = 0.049). No differences were observed in any of the variables recorded preFFT and 20 min postFFT. Conclusions: While mechanical variables indicating muscle fatigue were reduced 4 and 10 min postFFT, pre-exercise jump ability only really started to recover 20 min after FFT although not reaching pre-exercise levels. This means that ideally intervals of around 20 min of rest should be implemented between training bouts.

Physiological Responses at 15 Minutes of Recovery after a Session of Functional Fitness Training in Well-Trained Athletes

“…High-intensity functional training, also known as Functional Fitness training (FFT), is a training modality based on different exercises of muscular strengthening executed in different movement planes (FFTstrength), such as Olympic and power lifting, calisthenic, plyometric and gymnastic exercises, and on intervallic exercises of aerobic training (FFTendurance), such as running, rowing, cycling, rope jumping, etc. [ 1 , 2 ]. FFT workouts are performed in circuits at high intensity, with the aim of completing a certain predetermined number of repetitions in the shortest time possible (“rounds for time” or “RFT”) or completing as many repetitions of a set of exercises as possible within a certain pre-set time (“as many rounds as possible” or “AMRAP”) [ 3 , 4 ].…”

“…The physiological responses of this training modality have been analysed in different studies, showing high values of heart rate (HR) (90–95% HRmax), rating of perceived exertion (RPE) (RPE values > 8/10, RPE values > 15/20) and blood lactate concentration (>10 mmol·L −1 ) [ 2 , 7 , 8 , 9 ]. Moreover, acute cardiovascular responses do not vary among “workouts of the day” (WOD) based on the two most used training structures: RFT vs. AMRAP (10).…”

“…The interest in knowing the recovery times after an exercise session, leads us to ask the following question: how long does it take to recover pre-exercise values after a FFT workout in the same day? In this regard, García-Fernández et al (2021) [ 2 ] analysed muscle recovery up to 20 min after conducting a single FFT workout in trained adults. Their results showed a significant decrease in jumping capacity until minute 10 after FFT workout.…”

“…Their results showed a significant decrease in jumping capacity until minute 10 after FFT workout. However, after 20 min of recovery, the values began to recover without reaching the baseline levels [ 2 ]. However, they did not find the exact point where the values start to recover, which could be slightly above 10 min, at the midpoint (between 10 and 20 min) and slightly below 20 min.…”

“…To be able to calculate that point where recovery begins more accurately, it would be possible to determine an approximate rest to face another FFT workout with a recovery that guarantees the lowest residual fatigue and deterioration of the performance capacity, since muscle fatigue could reduce the exercise execution velocity, thereby altering the correct biomechanics and increasing the risk of injury [ 16 ]. Nevertheless, although the quantification of muscle fatigue in the study of García-Fernández et al (2021) [ 2 ] was measured through the widely used method of countermovement jump (CMJ), this method only assesses the mechanical variables related to the lower limbs, and it does not gather information about muscle fatigue in the upper limbs. Since the entire body is used in the FFT workouts, it is important to be able to measure muscle fatigue in the whole body, using, for example, the changes of velocity with respect to 1 m·s −1 of the mean propulsive velocity (MPV) [ 17 ].…”