Isometric Midthigh Pull Performance Is Associated With Athletic Performance and Sprinting Kinetics in Division I Men and Women's Basketball Players.

Townsend, JR, Bender, D, Vantrease, WC, Hudy, J, Huet, K, Williamson, C, Bechke, E, Serafini, PR, and Mangine, GT. Isometric midthigh pull performance is associated with athletic performance and sprinting kinetics in Division I men and women's basketball players. J Strength Cond Res 33(10): 2665-2673, 2019- The relationships between isometric mid-thigh pull (IMTP) force, athletic performance measures, and sprint kinetics in Division I men's and women's basketball players were investigated. Twenty-three (male = 8, female = 15) Division 1 basketball players completed a maximal 20-m sprint trial while tethered to a device that provided kinetic feedback (peak and average sprinting power, velocity and force). Additionally, 1 repetition maximum (1RM) front squat, 1RM hang clean, vertical jump height, and agility (proagility and lane agility) tests were performed. Rate of force development (RFD) at 50, 100, 150, 200 and 250 milliseconds of IMTP and peak force (PF) were also collected. Pearson's product-moment correlation analysis was used to examine the relationships between these measures. Significant (p ≤ 0.05) relationships were observed between IMTP PF and sprint time over all distances (5-20 m; r = -0.62 to 0.69), average sprint velocity (r = 0.50-0.70), peak sprint velocity (r = 0.50-0.54), average sprint force (r = 0.48-0.69), and average sprint power (r = 0.62-0.73). Sprinting kinetic measures (average force and power) over the first 5 m were also significantly (p ≤ 0.05) related to IMTP RFD (50-250 ms; r = 0.42-0.62). Results indicate that IMTP variables are significantly associated with 20-m sprint kinetics. Specifically, IMTP RFD appears to be related to the initial acceleration kinetics of a sprint. Strength and conditioning professionals can possibly implement the IMTP for improved assessment and monitoring of athletic performance and training.

A Resisted Sprint Improves Rate of Force Development During a 20-m Sprint in Athletes.

Mangine, GT, Huet, K, Williamson, C, Bechke, E, Serafini, P, Bender, D, Hudy, J, and Townsend, J. A resisted sprint improves rate of force development during a 20-m sprint in athletes. J Strength Cond Res 32(6): 1531-1537, 2018-This study examined the effect of a resisted sprint on 20-m sprinting kinetics. After a standardized warm-up, 23 (male = 10, female = 13) Division I basketball players completed 3 maximal 20-m sprint trials while tethered to a robotic resistance device. The first sprint (S1) used the minimal, necessary resistance (1 kg) to detect peak (PK) and average (AVG) sprinting power (P), velocity (V), and force (F); peak rate of force production (RFD) was also calculated. The second sprint (S2) was completed against a load equal to approximately 5% of the athlete's body mass. Minimal resistance (1 kg) was again used for the final sprint (S3). Approximately 4-9 minutes of rest was allotted between each sprint. Separate analyses of variance with repeated measures revealed significant (p ≤ 0.05) main effects for all sprinting kinetic measures except VPK (p = 0.067). Compared with S1, increased (p < 0.006) 20-m sprint time (3.4 ± 4.9%), PAVG (115.9 ± 33.2%), PPK (65.7 ± 23.7%), FAVG (134.1 ± 34.5%), FPK (65.3 ± 16.2%), and RFD (71.8 ± 22.2%) along with decreased (p < 0.001) stride length (-21 ± 15.3%) and VAVG (-6.6 ± 4.6%) were observed during S2. During S3, only RFD was improved (5.2 ± 7.1%, p < 0.001) compared with S1. In conclusion, completing a short, resisted sprint with a load equating to 5% of body mass before a short sprint (∼20-meters) does not seem to affect sprinting time or kinetics. However, it does appear to enhance RFD.

INTERSESSION RELIABILITY OF UPPER EXTREMITY ISOKINETIC PUSH-PULL TESTING.

BACKGROUND: Based on the frequency pushing and pulling patterns are used in functional activities, there is a need to establish an objective method of quantifying the muscle performance characteristics associated with these motions, particularly during the later stages of rehabilitation as criteria for discharge. While isokinetic assessment offers an approach to quantifying muscle performance, little is known about closed kinetic chain (CKC) isokinetic testing of the upper extremity (UE). PURPOSE: To determine the intersession reliability of isokinetic upper extremity measurement of pushing and pulling peak force and average power at slow (0.24 m/s), medium (0.43 m/s) and fast (0.61 m/s) velocities in healthy young adults. The secondary purpose was to compare pushing and pulling peak force (PF) and average power (AP) between the upper extremity limbs (dominant, non-dominant) across the three velocities. METHODS: Twenty-four physically active men and women completed a test-retest (>96 hours) protocol in order to establish isokinetic UE CKC reliability of PF and AP during five maximal push and pull repetitions at three velocities. Both limb and speed orders were randomized between subjects. RESULTS: High test-retest relative reliability using intraclass correlation coefficients (ICC2, 1) were revealed for PF (.91-.97) and AP (.85-.95) across velocities, limbs and directions. PF typical error (% coefficient of variation) ranged from 6.1% to 11.3% while AP ranged from 9.9% to 26.7%. PF decreased significantly (p < .05) as velocity increased whereas AP increased as velocity increased. PF and AP during pushing were significantly greater than pulling at all velocities, however the push-pull differences in PF became less as velocity increased. There were no significant differences identified between the dominant and nondominant limbs. CONCLUSION: Isokinetically derived UE CKC push-pull PF and AP are reliable measures. The lack of limb differences in healthy normal participants suggests that clinicians can consider bilateral comparisons when interpreting test performance. The increase in pushing PF and AP compared to pulling can be attributed to the muscles involved and the frequency that pushing patterns are used during functional activities. LEVEL OF EVIDENCE: 3.