Techniques and considerations for determining isoinertial upper‐body power

Association Between Performance in Muscle Fitness Field Tests and Skeletal Muscle Mass in Soldiers

INTRODUCTION

Muscle strength and muscle endurance are important fitness components related to safe and efficient execution of physically demanding military work. In soldiers, these components are traditionally measured from simple field tests like push-ups, sit-ups, and pull-ups. However, the validity of such muscle fitness field tests is questioned due to reports of low association between test performance and the ability to conduct strength demanding military work (eg, lift and carry tasks). It is therefore necessary to study, develop, and implement more valid field tests, which are still feasible for mass testing in the military. Skeletal muscle mass (SMM) is an important physiological component related to maximal muscle force generation (strength). Thus, an alternative way of validating muscle fitness field tests is by comparisons against SMM. The purpose of the present study was to investigate the association between SMM and performance in five muscle fitness field tests.

MATERIALS AND METHODS

A total of 275 military cadets (including 27 women) participated in this method comparison study. The field tests included push-ups, sit-ups, pull-ups (vertical for men, horizontal for women), standing medicine ball throw, and Sargent jump (peak power and jump height). SMM was estimated from bioelectrical impedance analysis and expressed in absolute values (kg) or relative to body mass. Pearson correlation coefficients (r) were calculated to investigate associations between SMM and performance in the five field tests. The study was submitted to the Regional Committee for Medical and Health Research Ethics prior to startup, and the Committee considered the study to be exempted from notification. The study was reviewed and approved by the Norwegian Social Science Data Services.

RESULTS

In men, the highest correlation against absolute SMM was found for the Sargent jump (peak power) and the medicine ball throw (r = 0.71 and 0.54, respectively). The same trend was evident for women (r = 0.85 and 0.61, respectively) and for the two genders combined (r = 0.85 and 0.79, respectively). All these r-values were significant (P < 0.001). In men, the highest r against relative SMM was found for pull-ups (r = 0.50, P < 0.001). The same pattern was found in women, but the association was not significant (r = 0.36, P = 0.07). The sit-ups test demonstrated low or nonsignificant associations with both absolute and relative SMM.

CONCLUSIONS

Among the five muscle fitness field tests investigated, the Sargent jump (peak power) and the medicine ball throw demonstrated the strongest correlation coefficients against absolute SMM. Thus, these two tests should be better alternatives for assessing relevant upper and lower body strength and power in soldiers compared with push-ups, pull-ups, and sit-ups. Pull-ups generally demonstrated the strongest correlation against relative SMM. Sit-ups demonstrated low or nonsignificant associations with both absolute and relative SMM. Consequently, the test should be considered for removal from military fitness test batteries or replaced by alternative abdominal tests that are more valid.

Influence of technique on upper body force and power production during medicine ball throws

This project examined the interrelationships between power production and upper body kinematics during a series of medicine ball push-press (MBP-P) throws. Twenty-five regular weight trainers (body mass = 86 ± 10 kg) performed a series of ballistic vertical MBP-P throws at loads representing 5% and 10% of their assessed 5RM bench press. Throws were performed lying supine on a force platform (1 kHz) with upper body kinematics assessed using standard infra-red motion capture techniques (0.5 kHz). Gross measures of performance and power production such as peak vertical ball velocity (Vel_peak), peak force (F_peak) and power (P_peak) were recorded during the propulsive phase of the movement. Comparative analyses indicated that despite significant reductions in Vel_peak from the 5% to 10% loads (P < 0.001), F_peak remained largely unchanged (P = 0.167). Analysis of inter-trial variability showed that the gross measures of performance and power were relatively stable (Coefficient of Variation [CV%] <13%), while most upper limb segmental kinematics varied considerably between trials (CV% up to 70%). This project highlights the complexity of the relationships between power production and upper body kinematics during light load ballistic MBP-P throwing. Additionally, it shows how trained athletes can achieve similar outcomes during ballistic movements using a variety of movement strategies.

Comparison Between Bench Press Throw and Ballistic Push-up Tests to Assess Upper-Body Power in Trained Individuals

Bartolomei, S, Nigro, F, Ruggeri, S, Malagoli Lanzoni, I, Ciacci, S, Merni, F, Sadres, E, Hoffman, JR, and Semprini, G. Comparison between bench press throw and ballistic push-up tests to assess upper-body power in trained individuals. J Strength Cond Res 32(6): 1503-1510, 2018-The purpose of this study was to validate the ballistic push-up (BPU) test performed with hands on a force plate as a method to measure upper-body power. Twenty-eight experienced resistance-trained men (age = 25.4 ± 5.2 years; body mass = 78.5 ± 9.0 kg; body height = 179.6 ± 7.8 cm) performed, 2 days apart, a bench press 1 repetition maximum (1RM) test and upper-body power tests. Mean power (MP) and peak power (PP) were assessed using the bench press throw (BT) test and the BPU test performed in randomized order. The area under the force/power curve (AUC) obtained at BT was also calculated. Power expressed at BPU was estimated using a time-based prediction equation. Mean force and the participant's body weight were used to predict the bench press 1RM. Pearson product-moment correlations were used to examine relationships between the power assessment methods and between the predicted 1RM bench and the actual value. Large correlations (0.79; p < 0.001) were found between AUC and MP expressed at BPU. Large correlations were also detected between MP and PP expressed at BT and BPU (0.75; p < 0.001 and 0.74; p < 0.001, respectively). Very large correlations (0.87; p < 0.001) were found between the 1RM bench and the 1RM predicted by the BPU. Results of this study indicate that BPU represents a valid and reliable method to estimate the upper-body power in resistance-trained individuals.

Reliability of a New Medicine Ball Throw Power Test

The purpose of this study was to examine the reliability of a new upper body medicine ball push-press (MBP-P) test. Twenty-three strength trained volunteers performed a series of supine MBP-P throws using loads representing 5% and10% of their 5RM bench press (5 repetitions at each load). Throws were performed on a force platform (2000 Hz), with medicine ball kinematic data collected using a high-speed motion capture (500 Hz). Testing was repeated after 7-10 days to quantify intertest reliability. Maximal force (F_max), impulse at F_max, time to F_max, and maximum rate of force development (RFD_max) were all calculated from the force platform outputs, with maximum ball velocity (Vel_max) and maximum ball acceleration (Accel_max) developed from the kinematic data. Reliability was assessed using intraclass correlation (ICC), coefficient of variation (%CV), and typical error. Medicine ball kinematic variables were more reliable (CV% = 2.6-5.3, ICC = 0.87-0.95) than the various force platform derived power variables (CV% = 7.9-26.7, ICC = 0.51-0.90). The MBP-P test produces reliable data and can be used to quantify many standard power based measures, with the key findings have implications for athletic populations requiring high velocity, light load upper body pushing power.

The acute effect of upper-body complex training on power output of martial art athletes as measured by the bench press throw exercise

The purpose of this study was to examine the acute effect of upper body complex training on power output, as well as to determine the requisite preload intensity and intra-complex recovery interval needed to induce power output increases. Nine amateur-level combat/martial art athletes completed four distinct experimental protocols, which consisted of 5 bench press repetitions at either: 65% of one-repetition maximum (1RM) with a 4 min rest interval; 65% of 1RM with an 8 min rest; 85% of 1RM with a 4 min rest; or 85% of 1RM with an 8 min rest interval, performed on different days. Before (pre-conditioning) and after (post-conditioning) each experimental protocol, three bench press throws at 30% of 1RM were performed. Significant differences in power output pre-post conditioning were observed across all experimental protocols (F=26.489, partial eta2=0.768, p=0.001). Mean power output significantly increased when the preload stimulus of 65% 1RM was matched with 4 min of rest (p=0.001), and when the 85% 1RM preload stimulus was matched with 8 min of rest (p=0.001). Moreover, a statistically significant difference in power output was observed between the four conditioning protocols (F= 21.101, partial eta²=0.913, p=0.001). It was concluded that, in complex training, matching a heavy preload stimulus with a longer rest interval, and a lighter preload stimulus with a shorter rest interval is important for athletes wishing to increase their power production before training or competition.

Optimal load maximizes the mean mechanical power output during upper extremity exercise in highly trained soccer players

The purpose of this study was to determine the optimal load for the maximal power output during the acceleration phase of a power movement in bench press (BP) exercises of highly trained soccer players at the beginning of a competition period. Fifteen professional male soccer players with an average age of 26.1 ± 3.9 years, an average height of 183.3 ± 6.7 cm, an average body mass of 78.8 ± 7.2 kg, and an average 1 repetition maximum (1RM) of 83.3 ± 11.2 kg were employed as subjects in this study. Maximal mean power output during a BP at 0, 10, 30, 50, 70, and 90% of their 1RM was measured to determine whether an optimal load exists that allows for the attainment of maximal power output. Three-dimensional upper extremity kinematic data were collected. Two force plates embedded in the floor and positioned below the bench were used to measure contact forces between the bench and ground during the lift. A repeated-measures analysis of variance was performed to determine power output differences at different percentages of the 1RM. The results of this study indicated that loads of 50% of the 1RM resulted in greater mean power output during the complete positive power movement. Loads at 30 and 50% of the 1RM resulted in greater mean power output computed from the acceleration phase of the lift than did all loads and were not statistically different from each other. However, individual soccer players did not reach the maximum power output with the same relative load. In conclusion, when soccer players develop muscular power toward the end of when the most important competitions are scheduled, dynamic effort strength training with the range of load from 30 to 50% of 1RM BP should be used. During the competition period, a load of 50% of a 1RM should be used in a BP to maintain muscular power over a wide load range.

Vertical jump as a tool in assessment of muscular power and anaerobic performance

Muscular strength and anaerobic power could be assessed by single and multiple vertical jump testing procedures. Anaerobic capacity measured by vertical jump testing is highly correlative with athletic performance, as compared to other anaerobic testing procedures. The most frequently used protocol with contact mat or force platform consists of single jump (i.e. squat jump, drop jump, countermovement jump) and serial jump testing with different duration. Measured variables include jump height and duration along with absolute and relative peak muscular power. Several investigators have clearly shown superior jump performance variables in elite athletes as compared to non-elite subjects. Differences obtained could be due to genetic factors and acute or prolonged efects of training regimen.