W5″ Test: A simple method for measuring mean power output in the bench press exercise.

The aims of the present study were to assess the validity and reliability of a novel simple test [Five Seconds Power Test (W5″ Test)] for estimating the mean power output during the bench press exercise at different loads, and its sensitivity to detect training-induced changes. Thirty trained young men completed as many repetitions as possible in a time of ≈5 s at 25%, 45%, 65% and 85% of one-repetition maximum (1RM) in two test sessions separated by four days. The number of repetitions, linear displacement of the bar and time needed to complete the test were recorded by two independent testers, and a linear encoder was used as the criterion measure. For each load, the mean power output was calculated in the W5″ Test as mechanical work per time unit and compared with that obtained from the linear encoder. Subsequently, 20 additional subjects (10 training group vs. 10 control group) were assessed before and after completing a seven-week training programme designed to improve maximal power. Results showed that both assessment methods correlated highly in estimating mean power output at different loads (r range: 0.86-0.94; p < .01) and detecting training-induced changes (R(2): 0.78). Good to excellent intra-tester (intraclass correlation coefficient (ICC) range: 0.81-0.97) and excellent inter-tester (ICC range: 0.96-0.99; coefficient of variation range: 2.4-4.1%) reliability was found for all loads. The W5″ Test was shown to be a valid, reliable and sensitive method for measuring mean power output during the bench press exercise in subjects who have previous resistance training experience.

Force Outputs during Squats Performed Using a Rotational Inertia Device under Stable versus Unstable Conditions with Different Loads.

The purpose of the study was to compare the force outputs achieved during a squat exercise using a rotational inertia device in stable versus unstable conditions with different loads and in concentric and eccentric phases. Thirteen male athletes (mean ± SD: age 23.7 ± 3.0 years, height 1.80 ± 0.08 m, body mass 77.4 ± 7.9 kg) were assessed while squatting, performing one set of three repetitions with four different loads under stable and unstable conditions at maximum concentric effort. Overall, there were no significant differences between the stable and unstable conditions at each of the loads for any of the dependent variables. Mean force showed significant differences between some of the loads in stable and unstable conditions (P < 0.010) and peak force output differed between all loads for each condition (P < 0.045). Mean force outputs were greater in the concentric than in the eccentric phase under both conditions and with all loads (P < 0.001). There were no significant differences in peak force between concentric and eccentric phases at any load in either stable or unstable conditions. In conclusion, squatting with a rotational inertia device allowed the generation of similar force outputs under stable and unstable conditions at each of the four loads. The study also provides empirical evidence of the different force outputs achieved by adjusting load conditions on the rotational inertia device when performing squats, especially in the case of peak force. Concentric force outputs were significantly higher than eccentric outputs, except for peak force under both conditions. These findings support the use of the rotational inertia device to train the squatting exercise under unstable conditions for strength and conditioning trainers. The device could also be included in injury prevention programs for muscle lesions and ankle and knee joint injuries.

Effect of vibration frequency on agonist and antagonist arm muscle activity.

PURPOSE: This study aimed to assess the effect of vibration frequency (f out) on the electromyographic (EMG) activity of the biceps brachii (BB) and triceps brachii (TB) muscles when acting as agonist and antagonist during static exercises with different loads. METHODS: Fourteen healthy men were asked to hold a vibratory bar as steadily as possible for 10 s during lying row (pulling) and bench press (pushing) exercise at f out of 0 (non-vibration condition), 18, 31 and 42 Hz with loads of 20, 50, and 80 % of the maximum sustainable load (MSL). The root mean square of the EMG activity (EMGRMS) of the BB and TB muscles was expressed as a function of the maximal EMGRMS for respective muscles to characterize agonist activation and antagonist coactivation. RESULTS: We found that (1) agonist activation was greater during vibration (42 Hz) compared to non-vibration exercise for the TB but not for the BB muscle (p < 0.05); (2) antagonist activation was greater during vibration compared to non-vibration exercise for both BB (p < 0.01) and TB (p < 0.05) muscles; (3) the vibration-induced increase in antagonist coactivation was proportional to vibration f out in the range 18-42 Hz and (4) the vibration-induced increase in TB agonist activation and antagonist coactivation occurred at all loading conditions in the range 20-80 % MSL. CONCLUSION: The use of high vibration frequencies within the range of 18-42 Hz can maximize TB agonist activation and antagonist activation of both BB and TB muscles during upper limb vibration exercise.

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.

Efecto de 8 semanas de entrenamiento con vibraciones en la tercera edad / Effect of an 8-week vibration training program in the elderly

Introducción. La actividad física ha demostrado ser beneficiosa para mantener o mejorar la autonomía en la tercera edad, de la misma forma que el ejercicio con vibración (EJVb) en personas adultas ha demostrado generar rápidos beneficios. En el presente estudio se analizan los efectos de un programa de 8 semanas de EJVb de volumen reducido en la autonomía y la fuerza en un grupo de personas de la tercera edad. Material y métodos. Veintitrés participantes (18 mujeres y 5 varones, de edad comprendida entre 70 y 92 años, con una media de edad de 81,2 años), realizaron un entrenamiento de 5 series de 30s con vibraciones mecánicas a 25Hz y 2mm de amplitud 3 veces a la semana durante 8 semanas. Se valoró la fuerza isométrica de los músculos extensores de rodilla mediante una galga del MuscleLab® y la autonomía mediante la prueba Expanded-Timed-Get-Up-and-Go (ETGUG), ambos antes, después de las 8 semanas de entrenamiento y 8 semanas después de haber cesado el entrenamiento. Resultados. Se detectaron diferencias significativas entre los 3 momentos de intervención en la fuerza, en el tiempo total en completar el ETGUG y en los diferentes parciales del mismo con excepción del tiempo parcial de levantarse y realización del giro. El EJVb mejoró significativamente el tiempo en completar el ETGUG y la fuerza tras 8 semanas de entrenamiento. Sin embargo, estos beneficios solo perduraron en la velocidad de la marcha, pero no en la fuerza. Discusión. Los resultados de la prueba ETGUG denotaron cambios significativos en su totalidad, sin embargo, analizando sus diferentes partes, encontramos 2 parciales (levantarse y giro) en los que las diferencias no fueron significativas, probablemente a que los resultados no dependen exclusivamente de la capacidad física del participante, sino que están también relacionados con la habilidad coordinativa. Conclusiones. Ocho semanas de EJVb de volumen reducido en personas de la tercera edad mejoraron la autonomía, pero no la fuerza isométrica(AU)

Introduction. Physical activity has been shown to maintain or improve autonomy in the elderly. It has also been demonstrated that vibration exercise in adults achieves rapid benefits. This study analyses the effects of an 8-week program of reduced volume vibration training on autonomy and strength in a group of elderly subjects. Material and methods. The 23 participants (18 women and 5 men, aged between 70 and 92 years, mean age 81.2 years) underwent a training program of five 30-second series of mechanical vibrations at 25Hz and 2mm wavelength three times a week for eight weeks. The isometric strength of the extensor muscles of the knee was assessed with a MuscleLab® gauge, and autonomy was tested with the “Expanded-Timed-Get-Up-and-Go” (ETGUG) test, both before and immediately after the eight weeks of the program and then eight weeks afterwards. Results. Significant differences were detected between the three time points in strength, and also in total time taken to complete the ETGUG and the various sections of the test, with the exception of the time taken to stand up and to turn. The vibration training program significantly improved the time taken to complete the ETGUG and strength after eight weeks of training. However, these benefits only endured for walking speed, not for strength. Discussion. The results of the ETGUG test revealed significant changes overall. However, in two sections (standing up and turning) the differences were not significant, probably because the results do not depend exclusively on participants’ physical capacity but are also related to their coordination skills. Conclusions. Eight weeks of reduced volume vibration training in the elderly improved autonomy, but not isometric strength(AU)

[Effect of an 8-week vibration training program in the elderly]. / Efecto de 8 semanas de entrenamiento con vibraciones en la tercera edad.

INTRODUCTION: Physical activity has been shown to maintain or improve autonomy in the elderly. It has also been demonstrated that vibration exercise in adults achieves rapid benefits. This study analyses the effects of an 8-week program of reduced volume vibration training on autonomy and strength in a group of elderly subjects. MATERIAL AND METHODS: The 23 participants (18 women and 5 men, aged between 70 and 92 years, mean age 81.2 years) underwent a training program of five 30-second series of mechanical vibrations at 25 Hz and 2 mm wavelength three times a week for eight weeks. The isometric strength of the extensor muscles of the knee was assessed with a MuscleLab(®) gauge, and autonomy was tested with the "Expanded-Timed-Get-Up-and-Go" (ETGUG) test, both before and immediately after the eight weeks of the program and then eight weeks afterwards. RESULTS: Significant differences were detected between the three time points in strength, and also in total time taken to complete the ETGUG and the various sections of the test, with the exception of the time taken to stand up and to turn. The vibration training program significantly improved the time taken to complete the ETGUG and strength after eight weeks of training. However, these benefits only endured for walking speed, not for strength. DISCUSSION: The results of the ETGUG test revealed significant changes overall. However, in two sections (standing up and turning) the differences were not significant, probably because the results do not depend exclusively on participants' physical capacity but are also related to their coordination skills. CONCLUSIONS: Eight weeks of reduced volume vibration training in the elderly improved autonomy, but not isometric strength.

The influence of serve characteristics on performance in men's and women's high-standard beach volleyball.

The precise influence of serve type and serve ball speed on beach volleyball performance is unclear. We examined the relationship between serve type and speed and their effectiveness during the 2008 Men's and Women's Open World Tour Tournament. Three hundred and seventy-eight and 375 serves performed by men and women respectively from the main draw tournament were analysed. Serve speed was recorded using a radar gun. Two expert observers recorded serve speed, serve mode, serve effectiveness and rally outcome. There was no relationship between serve speed and its effectiveness for men (r = -0.047, P > 0.05) and for women (r = -0.048, P > 0.05). However, there was a relationship between serve ball speed and its effectiveness both for men and women, when speed was categorised into three groups. There was a better balance between negative and positive outcomes at medium speeds for men and at low and high speeds for women. There was a relationship between ranking and serve ball speed only for women and between ranking and type of serve for both genders. There was no relationship between rally outcome and serve effectiveness. The combination of high ball speed and jump serve is characteristic of high ranking women but not of men.

Inter-rater reliability of muscle contractile property measurements using non-invasive tensiomyography.

Tensiomyography (TMG) is a relatively novel technique to assess muscle mechanical response based on radial muscle belly displacement consecutive to a single electrical stimulus. Although intra-session reliability has been found to be good, inter-rater reliability and the influence of sensor repositioning and electrodes placement on TMG measurements is unknown. The purpose of this study was to analyze the inter-rater reliability of vastus medialis muscle contractile property measurements obtained with TMG as well as the effect of inter-electrode distance (IED). Five contractile parameters were analyzed from vastus medialis muscle belly displacement-time curves: maximal displacement (Dm), contraction time (Tc), sustain time (Ts), delay time (Td), and half-relaxation time (Tr). The inter-rater reliability and IED effect on these measurements were evaluated in 18 subjects. Intra-class correlation coefficients, standard errors of measurement, Bland and Altman systematic bias and random error as well as coefficient of variations were used as measures of reliability. Overall, a good to excellent inter-rater reliability was found for all contractile parameters, except Tr, which showed insufficient reliability. Alterations in IED significantly affected Dm with a trend for all the other parameters. The present results legitimate the use of TMG for the assessment of vastus medialis muscle contractile properties, particularly for Dm and Tc. It is recommended to avoid Tr quantification and IED modifications during multiple TMG measurements.

A vibratory bar for upper body: feasibility and acute effects on EMGrms activity.

The purpose of this study was to determine the feasibility of a purpose-designed vibratory bar (VB) as a potential vibration training device and thereafter to assess its effects on upper-body muscles' electromyographic (EMG) activity during vibration. During session 1, 16 physically active males held the VB during the bench press exercise in an isometric extended position (EP) in the following vibration conditions selected in the inverter (i): no vibration (0), 20, 30, 40, and 50 Hzi. Maximal acceleration (Accmax), frequency (Freq), and peak-to-peak amplitude (Ampp-p) obtained at the center (C) and at the end (E) of the VB were assessed using an accelerometer. During session 2, EMGrms of the triceps, deltoid, and pectoralis major were recorded in EP and isometric flexion position (FP) at 0, 25, and 45 Hzi. The Accmax, Freq, and Ampp-p values ranged from 37.4 to 96.4 mxs, 18.5 to 30.8 Hz, and 4.6 to 6.1 mm, respectively. The accelerometer's position had a significant effect on the Accmax and Ampp-p. All Freq obtained at C and E were different (p < 0.001) to the Freqi. An increase (p < 0.05) in EMGrms was observed in both vibration conditions compared with 0 Hzi, except during 25Hzi for deltoid and pectoralis muscle in FP. Although no significant differences were found in any of the muscles between 45 Hzi and 25Hzi, the highest EMGrms was elicited at 45Hzi. Although the registered VBs' parameters seem appropriate for vibration training, the frequency in the FP should be higher than 25 Hzi to induce significant increases in EMGrms in deltoid and pectoralis muscles. The use of a vibratory bar may be a suitable system to simultaneously stimulate upper-body muscles.

A metronome for controlling the mean velocity during the bench press exercise.

Lifting velocity may have a great impact on strength training-induced adaptations. The purpose of this study was to validate a method including a metronome and a measurement tape as inexpensive tools for the estimation of mean lifting velocity during the bench press exercise. Fifteen subjects participated in this study. After determining their one repetition maximum (1RM) load, we estimated the maximum metronome rhythm (R) that each subject could maintain in the concentric phase for loads of 40 and 60% of 1RM. To estimate R, the 3 repetitions with highest concentric power, as measured by means of a linear encoder, were selected, and their average duration was calculated and converted to lifting rhythm in beats per minute (bpm) for each subject. The range of motion was measured using a regular tape and kept constant during all exercises. Subjects were instructed to begin with the barbell at arm lengths and lower it in correspondence with the metronome beep. They subsequently performed 5 repetitions at 3 different rhythms relative to R (50, 70, and 90% R) for each training load (40 and 60% of 1RM). A linear encoder was attached to the bar and used as a criterion to measure the vertical displacement over time. For each rhythm, the mean velocity was calculated with the metronome (time) and the reference distance and compared with that recorded by the linear encoder. The SEM for velocity between both testing methods ranged from 0.02 to 0.05 m.s (coefficient of variation, 4.0-6.4%; Pearson's correlation, 0.8-0.95). The present results showed that the use of a metronome and a measurement tape may be a valid method to estimate the mean velocity of execution during the bench press exercise. This simple method could help coaches and athletes achieve their strength training goals, which are partly determined by lifting velocity.