The Relationship between ACE, ACTN3 and MCT1 Genetic Polymorphisms and Athletic Performance in Elite Rugby Union Players: A Preliminary Study

Athletic performance is influenced by many factors such as the environment, diet, training and endurance or speed in physical effort and by genetic predisposition. Just a few studies have analyzed the impact of genotypes on physical performance in rugby. The aim of this study was to verify the modulation of genetic influence on rugby-specific physical performance. Twenty-seven elite rugby union players were involved in the study during the in-season phase. Molecular genotyping was performed for: angiotensin-converting enzyme (ACE rs4646994), alfa-actinin-3 (ACTN3 rs1815739) and monocarboxylate transporter 1 (MCT1 rs1049434) and their variants. Lean mass index (from skinfolds), lower-limb explosive power (countermovement jump), agility (505), speed (20 m), maximal aerobic power (Yo-yo intermittent recovery test level 1) and repeated sprint ability (12 × 20 m) were evaluated. In our rugby union players ACE and ACTN3 variants did not show any influence on athletic performance. MCT1 analysis showed that TT-variant players had the highest peak vertical power (p = 0.037) while the ones with the AA genotype were the fastest in both agility and sprint tests (p = 0.006 and p = 0.012, respectively). Considering the T-dominant model, the AA genotype remains the fastest in both tests (agility: p = 0.013, speed: p = 0.017). Only the MCT1 rs1049434 A allele seems to be advantageous for elite rugby union players, particularly when power and speed are required.

Effects of combined whole body vibration and resistance training on lower quadrants electromyographic activity, muscle strength and power in athletes

BACKGROUND

Whole body vibration (WBV) with resistance training is one of the increasing ways of gaining ankle and foot complex muscle strength and power for the rehabilitative and prophylactic purpose in athletes.

OBJECTIVE

The purpose of the study was to compare the effects of combined WBV and resistance training (RVE) with strength training alone (RE) on alteration of gastrocnemius lateralis and vastus medialis obliquus muscle activity and strength, and power performance in athletes.

METHODS

The study was performed on 23 university-level male athletes who were randomized into two groups as RVE (n = 12; age 22.2 ± 1.94 years) and RE (n = 11; age 21.60 ± 1.78 years). The training program was scheduled three times per week for six weeks (18 sessions). Gastrocnemius lateralis (GL) and vastus medialis obliquus (VMO) were measured for muscle activity and isometric strength with surface EMG device and handheld dynamometer respectively. Counter-movement jump (CMJ) was used for measuring power. All the participants were assessed for outcome measures at baseline and then after 6 weeks. Group (RVE vs. RE) by time (pre vs. post) effects were compared through a 2-way interaction utilizing mixed model repeated measure ANOVA.

RESULTS

After training, VMO muscle activity (group effects) increased significantly in the RVE group (p < 0.05). However, both the groups showed statistically significant time and group × time interaction effects for muscle activity of VMO, isometric strength (VMO and GL), and CMJ (p < 0.05).

CONCLUSION

WBV might serve as an adjunct modality for enhancement of the neuromuscular activity of the VMO muscle. However, RVE had no additive effect when compared to RE alone on muscle strength and power in athletes. The long-term impacts of combined WBV and resistance training on other foot and ankles muscle should be investigated in future studies.

Effects of Whole-Body Vibration Therapy on Quadriceps Function in Patients With Anterior Cruciate Ligament Reconstruction: A Systematic Review

CONTEXT

Quadriceps dysfunction is common for patients after anterior cruciate ligament reconstruction (ACLR). Whole-body vibration (WBV) could effectively treat quadriceps dysfunction.

OBJECTIVE

To summarize WBV protocols for patients with ACLR and to evaluate the effects of WBV on quadriceps function.

DATA SOURCES

PubMed, CINAHL, SportDiscus, Web of Science, Medline, and Embase were searched from inception to January 2020.

STUDY SELECTION

Randomized controlled trials recruiting patients with ACLR, using WBV as intervention, and reporting at least 1 of the following outcomes, strength, rate of torque development (RTD), and voluntary activation ratio of quadriceps, were included.

STUDY DESIGN

Systematic review.

EVIDENCE LEVEL

Level 3.

METHODS

This systematic review was reported according to PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. Quality of evidence was determined by PEDro criteria and GRADE system. Participant characteristics, interventions, and the relevant results of the included studies were extracted and synthesized in a narrative way.

RESULTS

In total, 8 studies were included. Of these, 2 studies had serious risk of bias. Five of 8 studies implemented a series of WBV program ranging from 2 to 10 weeks in duration, while the other 3 studies implemented a single session of WBV. Eight WBV protocols were reported. The reported outcomes consisted of quadriceps strength, RTD, and central activation ratio. WBV protocols were heterogeneous. Low quality of evidence supported that exclusive conventional rehabilitation was more effective than exclusive WBV therapy in increasing quadriceps strength. Low quality of evidence supported that WBV combined with conventional rehabilitation was more beneficial in increasing quadriceps strength when compared with conventional rehabilitation alone. Very low quality of evidence supported the efficacy of a single session of WBV on quadriceps function.

CONCLUSIONS

There is no standardized WBV protocol for patients with ACLR, and the effectiveness of WBV in rehabilitation on quadriceps function remains inconclusive.

Influence of energy cost and physical fitness on the preferred walking speed and gait variability in elderly women

Typically gait speed decreases and gait variability increases in elderly. The aim of this study was to define the influence of energy cost of walking on gait speed and of health-related physical fitness on gait variability. Thirty healthy young and older women were recruited in the study. Energy cost of walking (Net_CW) was analyzed with indirect calorimetry while a kinematic analysis was performed with an optoelectronic system to calculate gait variability (GV) during treadmill walking at different speeds. Gait speed was defined as the preferred walking speed (PWS) of the subject and health related physical fitness (HRPF) comprised body fat, strength, flexibility, and cardiorespiratory fitness. In healthy elderly women, the coefficient of variation of step width was found to be a better indicator of GV than stride time, stride length and double support coefficients of variation. GV was not affected by age allowing a high PWS. Furthermore, significant associations, adjusted for age, body mass index and number of falls, were identified neither between Net_CW and the PWS, nor between HRPF and GV; only a significant association was found between hand-grip strength and gait stability. Findings highlighted the importance to evaluate hand-grip strength as an indicator of gait efficiency.

Effects of Heavy Squat Training on a Vibration Platform on Maximal Strength and Jump Performance in Resistance-Trained Men

Hammer, RL, Linton, JT, and Hammer, AM. Effects of heavy squat training on a vibration platform on maximal strength and jump performance in resistance-trained men. J Strength Cond Res 32(7): 1809-1815, 2018-The purpose of this investigation was to determine maximal strength and jump performance outcomes of heavy squat training on a low-amplitude (<1.0 mm peak-to-peak) vibration platform (VP). Nineteen recreationally resistance-trained college-aged men (22.3 ± 1.66 years) completed the 6-week study. Participants were randomly assigned to 1 of 2 training groups: SQT (n = 10) performed conventional back squats on the floor and SQTV (n = 9) performed back squats on the VP. Supervised training took place over 12 sessions (2 d·wk), which used an aggressive strength development protocol (85-95% 1 repetition maximum [1RM]), which was identically followed by both groups. After the intervention, both groups showed (via t-test) a marked increase (p < 0.001) in 1RM squat strength (SQT = 34.5 kg vs. SQTV = 36.2 kg), but there was no significant difference (via mixed analysis of variance) between groups (p = 0.875). Standing broad jump performance increased by an average of 5-6 cm, but was not significantly changed in either group (SQT; p = 0.199, SQTV; p = 0.087). In conclusion, squats performed with whole body vibration (WBV) were not superior to conventional squats with respect to maximal strength and jump performance outcomes. It seems that there was no additive effect of superimposed WBV training on strength beyond that caused by strength training alone. This study can help strength conditioning professionals and athletes make an informed decision on whether to invest in a VP and use WBV as an alternative or a complementary mode of training.

Metabolic effect of bodyweight whole-body vibration in a 20-min exercise session: A crossover study using verified vibration stimulus

The ability of whole body vibration (WBV) to increase energy expenditure (EE) has been investigated to some extent in the past using short-term single exercises or sets of single exercises. However, the current practice in WBV training for fitness is based on the execution of multiple exercises during a WBV training session for a period of at least 20 min; nevertheless, very limited and inconsistent data are available on EE during long term WBV training session. This crossover study was designed to demonstrate, in an adequately powered sample of participants, the ability of WBV to increase the metabolic cost of exercise vs. no vibration over the time span of a typical WBV session for fitness (20 min). Twenty-two physically active young males exercised on a vibration platform (three identical sets of six different exercises) using an accelerometer-verified vibration stimulus in both the WBV and no vibration condition. Oxygen consumption was measured with indirect calorimetry and expressed as area under the curve (O_2(AUC)). Results showed that, in the overall 20-min training session, WBV increased both the O_2(AUC) and the estimated EE vs. no vibration by about 22% and 20%, respectively (P<0.001 for both, partial eta squared [η²] ≥0.35) as well as the metabolic equivalent of task (+5.5%, P = 0.043; η² = 0.02) and the rate of perceived exertion (+13%, P<0.001; ŋ² = 0.16). Results demonstrated that vibration is able to significantly increase the metabolic cost of exercise in a 20-min WBV training session.

Effect of Segment-Body Vibration on Strength Parameters

Background

In this study, we examine the biomechanical advantage of combining localized vibrations to hamstring muscles involved in a traditional resistance training routine.

Methods

Thirty-six male and female participants with at least 2 years of experience in resistance training were recruited from the German Sport University Cologne. The participants were randomized into two training groups: vibration training group (VG) and traditional training group (TTG). Both groups underwent a 4-week training phase, where each participant worked out at 70 % of the individual 1 repeat maximum (RM—maximum load capacity of a muscle for one lift to fatigue) (4 sets with 12 repetitions each). For participants in the VG group, local vibration was additionally applied directly to hamstring muscles during exercise. A 2-week examination phase preceded the pretests. After the pretests, the subjects underwent a prescribed training for 4 weeks. At the conclusion of the training, a 2-week detraining was imposed and then the study concluded with posttests and retest.

Results

The measured parameters were maximum isometric force of the hamstrings and maximum range of motion and muscle tension at maximum knee angle. The study revealed a significant increase in maximum isometric force in both training groups (VG = 21 %, TTG = 14 %). However, VG groups showed an increase in their range of motion by approximately 2 %. Moreover, the muscle tension at maximum knee angle increased less in VG (approximately 35 %) compared to TG (approximately 46 %).

Conclusions

We conclude that segment-body vibrations applied in resistance training can offer an effective tool to increase maximum isometric force, compared to traditional training. The cause for these findings can be attributed to the additional local vibration stimulus.

Small and inconsistent effects of whole body vibration on athletic performance: a systematic review and meta-analysis

Purpose

We quantified the acute and chronic effects of whole body vibration on athletic performance or its proxy measures in competitive and/or elite athletes.

Methods

Systematic literature review and meta-analysis.

Results

Whole body vibration combined with exercise had an overall 0.3 % acute effect on maximal voluntary leg force (−6.4 %, effect size = −0.43, 1 study), leg power (4.7 %, weighted mean effect size = 0.30, 6 studies), flexibility (4.6 %, effect size = −0.12 to 0.22, 2 studies), and athletic performance (−1.9 %, weighted mean effect size = 0.26, 6 studies) in 191 (103 male, 88 female) athletes representing eight sports (overall effect size = 0.28). Whole body vibration combined with exercise had an overall 10.2 % chronic effect on maximal voluntary leg force (14.6 %, weighted mean effect size = 0.44, 5 studies), leg power (10.7 %, weighted mean effect size = 0.42, 9 studies), flexibility (16.5 %, effect size = 0.57 to 0.61, 2 studies), and athletic performance (−1.2 %, weighted mean effect size = 0.45, 5 studies) in 437 (169 male, 268 female) athletes (overall effect size = 0.44).

Conclusions

Whole body vibration has small and inconsistent acute and chronic effects on athletic performance in competitive and/or elite athletes. These findings lead to the hypothesis that neuromuscular adaptive processes following whole body vibration are not specific enough to enhance athletic performance. Thus, other types of exercise programs (e.g., resistance training) are recommended if the goal is to improve athletic performance.

The influence of preset frequency, loading condition, and exercise type on the mechanical behavior of a novel vibratory bar

This study aimed to analyze the influence of different vibration frequencies, loading conditions, and exercise types on the mechanical behavior of a novel vibratory bar (VB). Fourteen healthy men were asked to hold the VB during lying row (pulling) and bench press (pushing) static exercise as steadily as possible for 10 seconds with loads of 20, 50, and 80% of the maximum sustained load (MSL) and at preset vibration frequencies (f(in)) of 20, 35, and 50 Hz. Root mean square vibration acceleration (a(RMS)), peak-to-peak displacement (D), and frequency (f(out)) were gained from a 3-dimensional accelerometer fixed to the VB. Increasing vibration frequency (from 20 to 50 Hz) resulted in a progressive and sizeable increase in VB a(RMS) and f(out) (both p ≤ 0.001) with smaller variations of D (≤5.9%, p ≤ 0.001). Adding weight to the VB (progressive overload from 20 to 80% MSL) did not affect D and minimally altered a(RMS) (<4.2%, p = 0.014) and f(out) (<1.7%, p = 0.002). Altering the type of exercise (pulling vs. pushing) did not affect VB a(RMS), D, and f(out). In conclusion, this study establishes the validity of a novel VB and legitimates its use for effective and safe upper-body static exercise with a wide range of vibration frequencies and loading conditions in the context of physical training or rehabilitation.

Progressive-overload whole-body vibration training as part of periodized, off-season strength training in trained women athletes

The purpose was to examine the effects of progressive-overload, whole-body vibration (WBV) training on strength and power as part of a 15-week periodized, strength training (ST) program. Eighteen collegiate women athletes with ≥1 year of ST and no prior WBV training participated in the crossover design. Random assignment to 1 of the 2 groups followed pretests of seated medicine ball throw (SMBT), single-leg hop for distance (LSLH, RSLH), countermovement jump (CMJ), 3 repetition maximum (3RM) front squat (FS), pull-up (PU), and 3RM bench press (BP). Whole-body vibration was two 3-week phases of dynamic and static hold body weight exercises administered 2 d·wk in ST sessions throughout the 15-week off-season program. Total WBV exposure was 6 minutes broken into 30-second bouts with 60-second rest (1:2 work-to-relief ratio). Exercises, frequency, and amplitude progressed in intensity from the first 3-week WBV training to the second 3-week phase. Repeated-measures analysis of variances were used to analyze the SMBT, CMJ, LSLH, RSLH, FS, PU, and BP tests. Alpha level was p ≤ 0.05. Front squat, LSLH, and RSLH increased (p = 0.001) from pre- to posttest; FS increased from mid- to posttest. Pull-up increased (p = 0.008) from pre- to posttest. Seated medicine ball throw and BP showed a trend of increased performance from pre- to posttest (p = 0.11). Two 3-week phases of periodized, progressive-overload WBV + ST training elicited gains in strength and power during a 15-week off-season program. Greatest improvements in performance tests occurred in the initial WBV phase. Implementing WBV in conjunction with ST appears to be more effective in the early phases of training.

Effect of a combination of whole-body vibration and low resistance jump training on neural adaptation

This study investigated and compared the effects of an eight-week program of whole body vibration combined with counter-movement jumping (WBV + CMJ) or counter-movement jumping (CMJ) alone on players. Twenty-four men's volleyball players of league A or B were randomized to the WBV + CMJ or CMJ groups (n = 12 and 12; mean [SD] age of 21.4 [2.2] and 21.7 [2.2] y; height of 175.6 [4.6] and 177.6 [3.9] cm; and weight, 69.9 [12.8] and 70.5 [10.7] kg, respectively). The pre- and post-training values of the following measurements were compared: H-reflex, first volitional (V)-wave, rate of electromyography rise (RER) in the triceps surae and absolute rate of force development (RFD) in plantarflexion and vertical jump height. After training, the WBV + CMJ group exhibited increases in H reflexes (p = 0.029 and <0.001); V-wave (p < 0.001); RER (p = 0.003 and <0.001); jump height (p < 0.001); and RFD (p = 0.006 and <0.001). The post-training values of V wave (p = 0.006) and RFD at 0-50 (p = 0.009) and 0-200 ms (p = 0.008) in the WBV + CMJ group were greater than those in the CMJ group. This study shows that a combination of WBV and power exercise could impact neural adaptation and leads to greater fast force capacity than power exercise alone in male players.

The effects of whole-body vibration on the cross-transfer of strength

This study investigated whether the use of superimposed whole-body vibration (WBV) during cross-education strength training would optimise strength transfer compared to conventional cross-education strength training. Twenty-one healthy, dominant right leg volunteers (21 ± 3 years) were allocated to a strength training (ST, m = 3, f = 4), a strength training with WBV (ST + V, m = 3, f = 4), or a control group (no training, m = 3, f = 4). Training groups performed 9 sessions over 3 weeks, involving unilateral squats for the right leg, with or without WBV (35 Hz; 2.5 mm amplitude). All groups underwent dynamic single leg maximum strength testing (1RM) and single and paired pulse transcranial magnetic stimulation (TMS) prior to and following training. Strength increased in the trained limb for the ST (41%; ES = 1.14) and ST + V (55%; ES = 1.03) groups, which resulted in a 35% (ES = 0.99) strength transfer to the untrained left leg for the ST group and a 52% (ES = 0.97) strength transfer to the untrained leg for the ST + V group, when compared to the control group. No differences in strength transfer between training groups were observed (P = 0.15). For the untrained leg, no differences in the peak height of recruitment curves or SICI were observed between ST and ST + V groups (P = 1.00). Strength training with WBV does not appear to modulate the cross-transfer of strength to a greater magnitude when compared to conventional cross-education strength training.