Relationship between Vertical Jump Height and Pennation Angle of the Rectus Femoris and Vastus Lateralis

Ultrasound assessments of pennation angle (PA) are commonly used to examine muscle architecture in young adults. Pennation of the lower-body musculature has been suggested to be an important predictor of functional performances for strength-related activities. However, limited data exist regarding how PA is associated with performance during a vertical jump test. PURPOSE: The purpose of this study was to determine the relationship between vertical jump height and PA of the rectus femoris (RF) and vastus lateralis (VL) muscles in healthy, young females. METHODS: Seventeen healthy, young females (age = 22 ± 3 years; mass = 61 ± 8 kg; height = 162 ± 6 cm) volunteered for this study. Participants visited the laboratory two times, separated by seven days at approximately the same time of day (±2 hours). During the first visit, participants were familiarized with the jumping procedures and underwent two diagnostic ultrasound assessments of the RF and VL muscles using a portable B-mode ultrasound imaging device and linear-array probe. During the second visit, participants performed three countermovement vertical jumps using a jump mat, which measured jump height (cm) based on flight time. All ultrasound images were scanned on the right leg with the probe oriented in the longitudinal plane. RF images were taken on the line at the midpoint between the anterior superior iliac spine and the proximal border of the patella. VL images were taken on the line at the midpoint between the greater trochanter and lateral epicondyle of the femur. For each scan, participants laid supine with the knee resting comfortably in extension, while the investigator (A.C.C.) placed the probe on the marked site to capture images of muscle pennation. Muscle fiber PA (°) was determined as the intersection of the fascicles with the deep aponeurosis. Each image was assessed three times, and the average value for PA was used for analysis. Pearson product-moment correlation coefficients (r) were used to examine the relationships between RF and VL PA and vertical jump height. RESULTS: PA values (mean ± SD) were 13.65 ± 3.25°for the RF and 20.53 ± 2.62°for the VL. Jump height was 34.90 ± 4.14 cm. There was a significant positive relationship between jump height and VL PA (r = 0.603, P = 0.010); however, there was no relationship between jump height and RF PA (r = 0.190, P = 0.466). CONCLUSION: The present findings of a significant positive relationship between jump height and VL PA suggest that pennation of the muscle fibers in the VL may play an important role in vertical jump performance. Strength and conditioning coaches and other practitioners may use these findings to help predict explosive jump-related capacities in college-aged females. Moreover, these findings highlight the need for training programs focused on increasing VL PA, as this may be helpful for improving vertical jump height in younger adults

Relationship between Vertical Jump Height and Muscle Size and Quality of the Rectus Femoris and Vastus Lateralis

Ultrasound assessments of muscle cross-sectional area (CSA) and echo intensity (EI) are commonly used to examine muscle size and quality in younger adults. Greater muscle CSA and lower EI values of the rectus femoris (RF) and vastus lateralis (VL) have been associated with improvements in lower-body muscle power and consequently, may play a significant role in the maximum height achieved during a vertical jump test. PURPOSE: To examine the relationships between vertical jump height and CSA and EI of the RF and VL muscles in healthy, young females. METHODS: Seventeen young females (age = 22 ± 3 years; mass = 61 ± 8 kg; height= 162 ± 6 cm) volunteered for this study. Participants visited the laboratory two times, separated by 7 days, at approximately the same time of day (±2 hours). During the first visit, participants were familiarized with the jumping procedures and underwent 2 diagnostic ultrasound assessments of the RF and VL muscles using a portable B-mode ultrasound imaging device and linear-array probe. During the second visit, participants performed 3 countermovement vertical jumps using a jump mat, which measured jump height (cm) based on flight time. All ultrasound images were scanned on the right leg with the probe oriented in the transverse plane. RF images were taken at 50% of the distance between the anterior superior iliac spine and the proximal border of the patella. VL images were taken at the midpoint between the greater trochanter and lateral epicondyle of the femur. For each scan, participants laid supine with the knee resting comfortably in extension, while the investigator (A.C.C.) moved the probe manually at a slow and continuous rate along the surface of the skin from the lateral to the medial sides of the muscle using a panoramic ultrasound imaging technique. Images were analyzed by determining a region of interest consisting of as much of the muscle as possible without any surrounding bone or fascia. CSA (cm2) and EI (AU) were measured from the same region of interest using a quantitative gray-scale analysis (black = 0, white = 255). Pearson product-moment correlation coefficients (r) were used to examine the relationships between RF and VL CSA and EI and vertical jump height. RESULTS: CSA and EI values (mean ± SD) were 9.61 ± 2.60 cm2 and 70.89 ± 8.12 AU for the RF and 21.85 ± 4.71 cm2 and 68.59 ± 6.69 AU for the VL, respectively. Jump height was 34.90 ± 4.14 cm. There was a significant positive relationship between jump height and VL CSA (r = 0.525, P = 0.030); however, there were no relationships between jump height and VL EI (r = -0.140, P = 0.592), RF CSA (r = 0.324, P = 0.204), and RF EI (r = -0.126, P = 0.629). CONCLUSION: The present findings of a significant positive relationship between jump height and VL CSA suggest that muscle size of the VL may play an important role in vertical jump performance. These findings highlight the need for training programs aimed to increase the size of the VL, as this may be beneficial for improving vertical jump height in younger adults

Reliability and Relationship between Ballistic Push-Up and Vertical Jump Peak Ground Reaction Force

Ballistic push-up (BPU) assessments are commonly used to evaluate athletic ability in young adults. It has been hypothesized that the peak ground reaction force (GRF) produced during a BPU may be an important predictor of upper-body strength and explosive performance capacities. However, limited data exist regarding the reliability of BPU GRF and how it relates to peak force values during a countermovement vertical jump (CMJ) test. PURPOSE: The purpose of this study was to examine the reliability of BPU GRF and its relationship with vertical jump GRF values. METHODS: Seventeen young, healthy females (age = 22 ± 3 years; mass = 61 ± 8 kg; height = 163 ± 7 cm) volunteered for this study. Participants visited the laboratory 2 times, separated by 2-7 days at approximately the same time of day (±2 hours). During each visit, participants performed 3 CMJs followed by 3 BPU assessments using a portable force plate. For the CMJs, participants were instructed to jump up as high as possible and explode off the force plate with maximal effort. For each BPU, participants adopted a prone position with hands positioned shoulder-width apart on the force plate. A wooden box of equal height to the force plate supported the participants’ knees. Participants descended from the “up” position by flexing their elbows until they were at an angle of 90°. After reaching this position, participants performed an explosive push-up action to full arm extension with their hands leaving the force plate. Peak GRF was determined during the CMJ and BPU assessments as the highest value from the force-time curve. The intraclass correlation coefficient (ICC) and standard error of measurement expressed as a percentage of the mean (SEM%) were calculated across visits to assess the reliability for BPU and CMJ peak GRF. The relationship between BPU and CMJ peak GRF values was determined by a Pearson product-moment correlation coefficient (r). RESULTS: Means ± SDs (averaged across both visits) were 266.89 ± 49.36 and 1325.78 ± 215.20 N, ICCs were 0.91 and 0.93, and SEM% values were 5.78 and 4.20% for the BPU and CMJ peak GRF data, respectively. A significant positive relationship was observed between BPU and CMJ peak GRF values (r = 0.832, P \u3c 0.001). CONCLUSION: These findings demonstrated that BPU and CMJ peak GRFs may be reliable measures for assessing dynamic upper- and lower-body force production in young, healthy adults. The significant relationship observed between the two tests indicated that those who produced greater forces in the BPU also produced greater forces in the CMJ. Therefore, in addition to upper-body performance, BPU GRF measurements may also be used to predict lower-body explosive performance capacities as assessed during a vertical jump test

Validity of a Linear Velocity Transducer for Measuring Peak Ground Reaction Force during a Countermovement Vertical Jump Test

ABSTRACT Linear velocity transducers offera portable and cost-effective means for quantifying peak ground reaction force (GRF) during a countermovement vertical jump (CMJ) test; however, their ability to provide valid vertical jump GRF measurements similar to those of a force plate (“gold standard”) remains unclear. PURPOSE: The purpose of this study was to examine the differences and relationship between force plate and linear velocity transducer measurements of peak GRF during a CMJ test. METHODS: Seventeen healthy, young females (age = 22 ± 3 years; mass = 61 ± 8 kg; height = 163 ± 7 cm) performed three CMJ assessments on an elevated platform where peak GRF was measured simultaneously from a force plate and a linear velocity transducer. The linear velocity transducer was attached to the posterior portion of a belt fastened around the participants’ waist. During the CMJs, participants stood on the force plate with feet shoulder width apart and hands positioned on the hips. Participants were not allowed to take any steps before performing the CMJ and a quick descending quarter-squat countermovement was allowed before the ascending take-off phase. For all CMJs, participants were verbally instructed to jump up as explosively as possible with both feet at the same time and land on the force plate in the starting position. Peak GRF from the force plate was determined as the highest value from the force-time curve. To calculate peak GRF using the linear velocity transducer, each participant’s body mass was entered into the transducer’s microcomputer. Estimated peak GRF was calculated and displayed by the microcomputer at the conclusion of each assessment. A Pearson product-moment correlation coefficient (r) was used to assess the relationship between the force plate and linear velocity transducer peak GRF values. The difference in peak GRF between the force plate and linear velocity transducer was analyzed by a paired samples t-test.RESULTS: Peak GRF values (mean ± SD) were 1309.93 ± 238.06 N for the force plate and 1338.24 ± 244.98 N for the linear velocity transducer. There was a significant positive relationship between the force plate and linear velocity transducer peak GRF values (r= 0.849, P\u3c 0.001). No significant difference in peak GRF was observed between devices (P= 0.392). CONCLUSION: These findings provide support that the linear velocity transducer may be a valid device for measuring peak GRF during a CMJ assessment in healthy, young females. Vertical jump GRF has been shown to be a significant predictor of explosive-type performances and thus, may be of vital importance for determining athletic ability. The linear velocity transducer used in the present study may provide researchers and practitioners with a relatively accurate, cost-effective, and portable measurement tool capable of enhancing the practicality and utility of these (typically lab based) measurements when analyzing vertical jump performance capacities of athletes in the field

Age-related Differences in Forearm Muscle Size and Handgrip Maximal and Rapid Force Characteristics

With handgrip strength being an important predictor of future disability and mortality, it is essential to expand our understanding of the age-related changes in handgrip strength characteristics and their underlying mechanisms. Previous studies have reported that decreases in muscle size of the forearm may contribute to age-related deficits in wrist flexion strength. However, we are aware of no previous studies that have examined the contribution of forearm muscle size to age-related differences in handgrip strength, and more specifically, the age-related differences in handgrip maximal and rapid force characteristics. PURPOSE: To determine the effects of age on forearm muscle size [muscle thickness (MT)] and handgrip maximal and rapid force characteristics in young and old females. METHODS: Ten young (age = 22 ± 3 years; height = 162 ± 8 cm; mass = 62 ± 9 kg) and 10 old (age = 68 ± 4 years; height = 160 ± 5 cm; mass = 68 ± 5 kg) females underwent two diagnostic ultrasound assessments followed by three isometric handgrip maximal voluntary contractions (MVCs) using an electronic handgrip dynamometer. Forearm MT (cm) was measured on the right arm using a portable B-mode ultrasound imaging device and linear-array probe. For each MVC, participants sat in an upright position and were instructed to squeeze the handgrip dynamometer with their right hand “as hard and fast as possible” for 3-4 seconds. Handgrip MVC peak force (PF; N) was calculated as the highest mean 500 ms epoch during the entire 3-4 second MVC plateau. Rate of force development (RFD; N·s-1) was calculated as the linear slope of the force-time curve over the time interval of 0-100 ms. Independent samples t-tests were used to compare demographic characteristics, MT, PF, and RFD between age groups. Pearson product-moment correlation coefficients (r) were used to examine the relationships between MT and PF and RFD. RESULTS: There were no differences between the young and old females for height (P = 0.521) or body mass (P = 0.090). The old females exhibited lower MT (old = 1.53 ± 0.22 cm; young = 1.76 ± 0.21 cm; P = 0.026), PF (old = 152.53 ± 28.37 N; young = 209.67 ± 39.08 N; P = 0.001), and RFD (old = 606.96 ± 248.41 N·s-1; young = 1154.04 ± 390.55 N·s-1; P = 0.002) than the young females. Significant positive relationships were observed between MT and PF (r = 0.470; P = 0.036) and RFD (r = 0.485; P = 0.030). CONCLUSION: These findings demonstrated that forearm muscle size and handgrip PF and RFD decrease in old age. The significant relationships observed between MT and PF and RFD in the young and old females perhaps suggest that these age-related declines in forearm muscle size may play an important role in the lower handgrip maximal and rapid force values observed in older adults. As a result, practitioners may consider implementing training programs aimed at increasing MT of the forearm in the elderly which may be beneficial for improving muscle size as well as handgrip maximal and rapid force production

Age-Related Differences in Vertical Jump Power and Muscle Size and Quality of the Vastus Lateralis

Previous studies have reported that decreases in muscle size and quality of the vastus lateralis (VL) may contribute to the lower vertical jump power observed in old compared to young males. However, we are aware of no previous studies that have examined the contribution of VL muscle size and quality to age-related power differences in females, nor have there been any studies that examined these differences between young, middle, and older age groups. PURPOSE: To determine the effects of age on vertical jump power and muscle size (cross-sectional area [CSA]) and quality (echo intensity [EI]) of the VL in young, middle-aged, and old females. METHODS: Twenty-six young (age = 22 ± 2 yr; height = 163 ± 7 cm; mass = 61 ± 8 kg), 30 middle-aged (36 ± 5 yr; 164 ± 7 cm; 62 ± 11 kg), and 23 old (71 ± 5 yr; 161 ± 5 cm; 59 ± 10 kg) females underwent two diagnostic ultrasound assessments followed by three countermovement vertical jumps (CMJs). Peak power output (Pmax; W) was measured during the CMJs using a portable force plate. VL CSA (cm2) and EI (AU) were measured on the right leg using a portable B-mode ultrasound imaging device and linear-array probe. One-way ANOVAs and post-hoc analyses were used to compare Pmax, CSA, and EI between age groups. Pearson product-moment correlation coefficients (r) were used to examine the relationships between Pmax and CSA and EI. RESULTS: Higher Pmax and CSA values were observed for the young (Pmax = 2257.40 ± 438.42 W; CSA = 20.59 ± 4.23 cm2) compared to the old (Pmax = 1098.55 ± 242.10 W; CSA = 10.69 ± 2.47 cm2) and middle-aged (Pmax = 1958.20 ± 341.87 W; CSA = 18.05 ± 4.24 cm2) and the middle-aged compared to the old (P ≤ 0.001-0.039). EI values for the young (104.29 ± 16.86 AU) and middle-aged (107.71 ± 17.30 AU) were lower than the old (128.35 ± 14.99 AU) (P \u3c 0.001), but they were not different from each other (P = 0.720). There was a significant positive relationship between Pmax and CSA (r = 0.830; P \u3c 0.001) and a significant negative relationship between Pmax and EI (r = -0.442; P \u3c 0.001). CONCLUSION: These findings demonstrated that vertical jump power and muscle size and quality decrease with age. The significant relationships observed between Pmax and CSA and EI perhaps suggest that these age-related declines in VL muscle size and quality may play an important role in the lower vertical jump power observed in middle-aged and older adults