Azael J. Herrero

Muscular adaptations after two different volumes of blood flow‐restricted training

This study aimed to gain an insight into the adaptations of muscle strength and skeletal muscle thickness after two different volumes of blood flow restriction training (BFRT), and compare them with high‐intensity training. The sample was divided into four groups: low‐volume, low‐intensity BFRT (BFRT LV); high‐volume, low‐intensity BFRT (BFRT HV); traditional high‐intensity resistance training (HIT); and a control group, which maintained their routine activities (CON). Leg extension one repetition maximum (1RM), isokinetic peak knee extension, and flexion torques at 60°/s and 180°/s as well as muscle thickness of the rectus femoris (RF) and vastus lateralis (VL) were assessed at baseline and after 5 weeks of training BFRT LV (7.03%, P < 0.05), BFRT HV (6.24%, P < 0.05) and HIT (18.86%, P < 0.001) groups increased 1RM performance, while no changes were observed in the CON group. Muscle thickness of the RF and VL was increased irrespective of the training group (7.5%, P < 0.001; and 9.9%, P < 0.001, respectively). We conclude that doubling the exercise volume with BFRT causes no further benefit with muscular size or strength. Although similar increases in muscle thickness were observed between training groups, HIT increased 1RM performance to a greater extent compared to either volume of BFRT.

Effects of whole-body vibration on muscle architecture, muscle strength, and balance in stroke patients: a randomized controlled trial.

ObjectiveThe aim of the present study was to analyze the effects of whole-body vibration on lower limb muscle architecture, muscle strength, and balance in stroke patients during a period of 3 mos. DesignThe inclusion criteria were having had ischemic or hemorrhagic stroke at least 6 mos before the study and a National Institutes of Health Stroke Scale score of greater than 1 and less than 20. The patients were randomly divided into two groups: an experimental group (n = 11, six men and five women; age, 62.4 ± 10.7 yrs; height, 1.64 ± 0.07 m; mass, 69.4 ± 12.9 kg) and a sham group (n = 9, five men and four women; age, 64.4 ± 7.6 yrs; height, 1.62 ± 0.07 m; mass, 75.0 ± 15.8 kg). The experimental group received a whole-body vibration treatment, with an increase in frequency, sets, and time per set during 17 sessions. The sham group performed the same exercises as that of the experimental group but was not exposed to vibration. Outcome variables included the muscle architecture (the rectus femoris, the vastus lateralis, and the medial gastrocnemius), the maximal isometric voluntary contraction of the knee extensors, and the Berg Balance Scale. ResultsThere were no significant differences between the groups on the primary outcomes of lower limb muscle architecture, muscle strength, and balance. ConclusionsIt seems that whole-body vibration exercise does not augment the increase in neuromuscular performance and lower limb muscle architecture induced by isometric exercise alone in stroke patients.

Short-term effect of plyometrics and strength training with and without superimposed electrical stimulation on muscle strength and anaerobic performance: A randomized controlled trial. Part II.

Herrero, AJ, Martín, J, Martín, T, Abadía, O, Fernández, B, and García-López, D. Short-term effect of plyometrics and strength training with and without superimposed electrical stimulation on muscle strength and anaerobic performance: A randomized controlled trial. Part II. J Strength Cond Res 24(6): 1616-1622, 2010-The purpose of this study was to compare the effects of combined strength and plyometric training with or without superimposed electromyostimulation (EMS) on muscle strength and anaerobic power. Twenty-nine subjects were randomly assigned to weight + plyometrics + EMS (EP), weight + plyometrics (VP), and control group (CG). Weight + plyometrics + EMS and VP performed 2 plyometric sessions and 2 weight training sessions per week throughout 4 weeks on a knee extension machine. Weight + plyometrics + EMS received EMS throughout the concentric phase of each action (120 Hz, 400 microseconds). Before, after training, and 2 weeks after the end of the training (detraining), maximal voluntary contraction, squat jump, countermovement jump, countermovement jump with free arms, and 20-minute sprint time were analyzed. After the training period, EP and VP increased their muscle strength (28.6 and 22.3%, respectively; p < 0.001). After the detraining period, this gain remained above baseline values (28.1 and 18.0%, respectively; p < 0.001 and p < 0.01). After training and detraining, muscle strength was higher in EP than in VP (p < 0.05). Vertical jump height was not modified for whichever group or test, except for the countermovement jump height with free arms, where a decrease for EP was observed after training (−6.3%; p < 0.001) and detraining (−5.5%; p < 0.001). Sprint performance improved in all groups in the detraining test (−0.8%; p < 0.05). If a low number of training sessions are carried out, superimposed EMS leads to a higher strength gain than voluntary training alone. However, if anaerobic power is an important aim of the training, EMS should be applied isometrically instead of superimposed EMS and combined with plyometrics.

Effects of different magnitudes of whole-body vibration on arm muscular performance.

Marín, PJ, Herrero, AJ, Sáinz, N, Rhea, MR, and García-López, D. Effects of different magnitudes of whole-body vibration on arm muscular performance. J Strength Cond Res 24(9): 2506-2511, 2010-The purpose of this study was to analyze the effects of different vibration magnitudes via feet on the number of repetitions performed, mean velocity, and perceived exertion during a set of elbow-extension exercise to failure (70% 1 repetition maximum [1RM] load). Twenty recreationally active students (14 men and 6 women) performed, in 3 different days, 1 elbow-extension set applying randomly 1 of the 3 experimental conditions: high magnitude (HM; 50 Hz and 2.51 mmp-p; 98.55 m·s−2), low magnitude (LM; 30 Hz and 1.15 mmp-p; 20.44 m·s−2) or control (Control, without vibration stimulus). Results indicate that the vibration via feet provides superimposed stimuli for elbow-extensor performance, enhancing the total number of repetitions performed in the HM and LM conditions, which was significantly higher (p ≤ 0.05) than that performed in the Control condition (21.5 and 18.1%, respectively). Moreover, there was a significant increase (p ≤ 0.05) in the average velocity for the whole set in the HM condition in comparison to the LM and Control conditions. This study provides evidence that an HM of vibration generates more neuromuscular facilitation than an LM. These data suggest that a vibration stimulus applied to the feet can result in positive improvements in upper body resistance exercise performance.

Whole-body vibration alters blood flow velocity and neuromuscular activity in Friedreich’s ataxia

The purpose of this study was to investigate the effects of whole‐body vibration (WBV) on blood flow velocity and muscular activity after different vibration protocols in Friedreich’s ataxia (FA) patients. After two familiarization sessions ten patients received six 3 min WBV treatments depending on a combination of frequency (10, 20 or 30 Hz) and protocol (constant or fragmented). Femoral artery blood flow velocity, vastus lateralis (VL) and vastus medialis (VM) electromyography (EMG), and rate of perceived exertion were registered. Peak blood velocity was increased with respect to basal values after 1, 2 and 3 min of WBV (14·8%, 18·8% and 19·7%, respectively, P < 0·001). Likewise, mean blood velocity was increased with respect to basal values after 1, 2 and 3 min of WBV (17·3%, 19·4% and 16·6%, respectively, P < 0·001). EMG amplitude of VL and VM was increased (39% and 23%, respectively, P < 0·05) and EMG frequencies decreased during the application of WBV. The results of this study suggest that higher frequencies (30 Hz) produce a greater increase in blood flow velocity and rate of perceived exertion. WBV is an effective method to increase blood flow and to activate muscle mass in patients with Friedreich’s ataxia, and could therefore be considered to be incorporated in rehabilitation programs of this collective.

Acute Effects of Whole-Body Vibration on Neuromuscular Responses in Older Individuals: Implications for Prescription of Vibratory Stimulation

Marín, PJ, Herrero, AJ, García-López, D, Rhea, MR, López-Chicharro, J, González-Gallego, J, and Garatachea, N. Acute effects of whole-body vibration on neuromuscular responses in older individuals: implications for prescription of vibratory stimulation. J Strength Cond Res 26(1): 232–239, 2012—The aim of this study was to analyze surface electromyography activity (sEMG) and rating of perceived exertion (RPE) responses in different muscles while standing on a vibrating platform producing oscillations of different frequencies and amplitudes. Twenty community-dwelling older adults (79.6 ± 3.2 years) took part in the research. Subjects were exposed to 12 different vibration treatments of 15 seconds separated by 1 minute of rest in random order to check the influence of frequency (25, 35, and 45 Hz) and amplitude (1 mm [low] and 3.1 mm [high]) vibration on sEMG signal and RPE. Additionally, the use of a soft pad was also examined for its influence on these measures. Three-factor analysis of variance for RPE and both lower and whole-body sEMGs revealed a significant amplitude main effect (p < 0.01), and soft mat effect (p < 0.01), and a significant frequency main effect (p < 0.01). The major findings were that sEMG and RPE increased with the acceleration of the vibration; moreover, the increments of sEMG were highly correlated with RPE. The results of this study suggest that using the RPE method after each exercise would allow exercise and health professionals to assess the intensity levels that correspond to the level of the vibratory program in older adults.

Interset stretching does not influence the kinematic profile of consecutive bench-press sets.

García-López, D, Izquierdo, M, Rodríguez, S, González-Calvo, G, Sainz, N, Abadía, O, and Herrero, AJ. Interset stretching does not influence the kinematic profile of consecutive bench-press sets. J Strength Cond Res 24(5): 1361-1368, 2010-This study was undertaken to examine the role of interset stretching on the time course of acceleration portion AP and mean velocity profile during the concentric phase of 2 bench-press sets with a submaximal load (60% of the 1 repetition maximum). Twenty-five college students carried out, in 3 different days, 2 consecutive bench-press sets leading to failure, performing between sets static stretching, ballistic stretching, or no stretching. Acceleration portion and lifting velocity patterns of the concentric phase were not altered during the second set, regardless of the stretching treatment performed. However, when velocity was expressed in absolute terms, static stretching reduced significantly (p <0.05) the average lifting velocity during the second set compared to the first one. Therefore, if maintenance of a high absolute velocity over consecutive sets is important for training-related adaptations, static stretching should be avoided or replaced by ballistic stretching.

Influence of "in series" elastic resistance on muscular performance during a biceps-curl set on the cable machine.

García-López, D, Herrero, AJ, González-Calvo, G, Rhea, MR, and Marín, PJ. Influence of “in series” elastic resistance on muscular performance during a biceps-curl set on the cable machine. J Strength Cond Res 24(9): 2449-2455, 2010-This study aimed to investigate the role of elastic resistance (ER) applied “in series” to a pulley-cable (PC) machine on the number of repetitions performed, kinematics parameters, and perceived exertion during a biceps-curl set to failure with a submaximal load (70% of the 1 repetition maximum). Twenty-one undergraduate students (17 men and 4 women) performed, on 2 different days, 1 biceps-curl set on the PC machine. Subjects were randomly assigned to complete 2 experimental conditions in a cross-over fashion: conventional PC mode or ER + PC mode. Results indicate ER applied “in series” to a PC machine significantly reduces (p < 0.05) the maximal number of repetitions and results in a smooth and consistent decline in mean acceleration throughout the set, in comparison to the conventional PC mode. Although no significant differences were found concerning intrarepetition kinematics, the ER trended to reduce (18.6%) the peak acceleration of the load. With a more uniformly distributed external resistance, a greater average muscle tension could have been achieved throughout the range of movement, leading to greater fatigue that could explain the lower number of maximal repetitions achieved. The application of force in a smooth, consistent fashion during each repetition of an exercise, while avoiding active deceleration, is expected to enhance the benefits of the resistance exercise, especially for those seeking greater increases in muscular hypertrophy.

WHOLE-BODY VIBRATION APPLIED DURING UPPER BODY EXERCISE IMPROVES PERFORMANCE

Abstract Marín, PJ, Herrero, AJ, Milton, JG, Hazell, TJ, and García-López, D. Whole-body vibration applied during upper body exercise improves performance. J Strength Cond Res 27(7): 1807–1812, 2013—Whole-body vibration (WBV) training has exercisers perform static and dynamic resistance training exercises on a ground-based platform. Exposure to WBV exposure has demonstrated benefits and no effect on lower body strength, power, and performance. The aim of this study was to determine if WBV exposure (50 Hz, 2.51 mm) has any potentiating effects postexercise by measuring the kinematic variables of a set of upper body elbow-extensor exercise (70% one-repetition maximum [1RM]) to volitional exhaustion. Sixteen recreationally active students (12 male and 4 female) performed 3 different experimental conditions on separate days. Each condition had the subjects perform 1 set of elbow-extension exercise to fatigue with 1 of 3 WBV treatments: WBV simultaneously during the set (AE); 60 seconds after application of WBV for 30 seconds (RE); and no WBV (CTRL). Kinematic parameters of each repetition were monitored by linking a rotary encoder to the highest load plate. The mean velocity and acceleration throughout the set and perceived exertion were analyzed. A significant increase (p < 0.05) was observed in the mean velocity for the whole set in the AE condition vs. the CTRL condition. The mean acceleration was significantly higher (p < 0.05) in the AE condition in comparison with RE (increased by 45.3%) and CTRL (increased by 50.4%) conditions. The positive effect induced by WBV on upper-limb performance is only achieved when the stimulus is applied during the exercise. However, WBV applied 60 seconds before upper body exercise results in no benefit.

Adaptation of perceptual responses to low-load blood flow restriction training

Abstract Martín-Hernández, J, Ruiz-Aguado, J, Herrero, AJ, Loenneke, JP, Aagaard, P, Cristi-Montero, C, Menéndez, H, and Marín, PJ. Adaptation of perceptual responses to low-load blood flow restriction training. J Strength Cond Res 31(3): 765–772, 2017—The purpose of this study was to determine the adaptive response of ratings of perceived exertion (RPE) and pain over 6 consecutive training sessions. Thirty subjects were assigned to either a blood flow restriction training (BFRT) group or a high-intensity resistance training (HIT) group. Blood flow–restricted training group performed 4 sets (30 + 15 + 15 + 15, respectively) of unilateral leg extension at an intensity of 20% one repetition maximum (1RM) while a restrictive cuff was applied to the most proximal part of the leg. The HIT group performed 3 sets of 8 repetitions with 85% 1RM. Ratings of perceived exertion and pain were assessed immediately after each exercise set along the 6 training sessions and were then averaged to obtain the overall RPE and pain per session. Statistical analyses showed significant main effects for group (p ⩽ 0.05) and time (p < 0.001). Ratings of perceived exertion values dropped from session 1 to session 6 in both BFRT (8.12 ± 1.3 to 5.7 ± 1.1, p < 0.001) and HIT (8.5 ± 1.2 to 6.40 ± 1.2, p < 0.001). Similar results were observed regarding pain ratings (BFRT: 8.12 ± 1.3 to 5.90 ± 1.55, p < 0.001; HIT: 6.22 ± 1.7 to 5.14 ± 1.42, p < 0.01). Our results indicate that RPE was higher after HIT, whereas differences did not reach significance regarding pain. These perceptual responses were attenuated over time, and the time course of this adaptive response was similar between BFRT and HIT. In summary, BFRT induces a marked perceptual response to training, comparable with that observed with HIT. However, this response becomes attenuated with continuous practice, leading to moderate values of RPE and pain. Perceptual responses may not limit the application of BFRT to highly motivated individuals.