Objectives: Correlational studies have linked distinct characteristics of lower body muscle structure (e.g. muscle thickness and pennation angle) to key variables attained during various tasks (e.g. squatting and jumping) which are beneficial to athletic development. The aim of this study was to explore relationships between lower body muscle structure and one-repetition maximum (1-RM) power clean. Design and Methods: 15 resistance trained subjects (13 males, 2 females) had three ultrasound images of their vastus lateralis (VL)and medial gastrocnemius (MG) musculature taken at rest before participating in a 1-RM power clean protocol on two occasions interspersed by 48-72 hours. Results: Intraclass correlation coefficients (ICC) demonstrated high within- and between-image reliability for the muscle structure measures (ICC ≥ 0.81, p < 0.001) and excellent between-session reliability for both the absolute and relative 1-RM power clean measurements (ICC = 0.96, p < 0.001). Significant moderate relationships were found between VL muscle thickness and relative 1-RM power clean (r = 0.506, p = 0.027), MG muscle thickness and absolute 1-RM power clean (ρ = 0.476, p = 0.036) and MG pennation angle and relative 1-RM power clean (ρ = 0.543, p = 0.018). Conclusion: Results suggest that developing thickness of the knee extensor musculature and both thickness and pennation angles of the plantar flexor musculature may augment 1-RM power clean performance. As suggested by previous research, this can be achieved by completing heavy resistance (i.e. strength) training with emphasis placed on improving both the magnitude and rate of lower body force development.

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Objectives: The aim of this study was to investigate the relationships between general speed and change of direction speed and ‘cricket specific’ speed tests and the relationships between jump performance and speed and change of direction ability in male academy cricketers. Design and Methods : Sixteen academy male cricketers (age: 17 ± 0.7 years; height: 176.9 ± 6.2 cm; mass: 72.2 ± 13.2 kg) per formed tests of 20 m sprint, 505 change of direction (COD) on both left and right legs, “quick single” with bat (WB) (17.68m), running-a-two WB, running-a-three WB, countermovement jump (CMJ), and drop jump (DJ). Results: Intra-class correlation coefficients (ICC’s) revealed high within-session reliability for all tests (ICC ≥ 0.92; p ≤ 0.001), except 0-5 m (ICC = 0.642; p ≤ 0.001) and 0-10 m (ICC = 0.708; p ≤ 0.001) tests. General speed tests showed strong relation ships to ‘cricket specific’ speed tests (20 m sprint - running-a-two; r = 0.951; p ≤ 0.01; 20 m sprint - running-a-three; r = 0.937; p ≤ 0.01; ‘quick single’; r = 0.951; p ≤ 0.01). Strong relationships were also observed between the 505 right foot COD times and all cricket specific tests (r = 0.909- 0.934; p ≤ 0.01). CMJ height showed the strongest correlations with: 20 m (r = -0.668; p ≤ 0.01); 505 left (r = -0.789; p ≤ 0.01); 505 right (r = -0.807; p ≤ 0.01); “quick single” WB (r = -0.739; p ≤ 0.01); running-atwo WB (r = -0.742; p ≤ 0.01); running-a-three (WB) (r = -0.733; p ≤ 0.01). Conclusions: The findings suggest that general speed and COD tests are highly appropriate to assess cricket specific qualities in youth cricketers.

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Objectives: To explore relationships between aspects of vastus lateralis (VL) and medial gastrocnemius (MG) muscle structure (muscle thickness, fascicle length and pennation angle) and isometric mid-thigh pull (IMTP) peak force capacity. Design and Methods: Fifteen male collegiate athletes (height 1.79 ± 0.05 m; body mass 82.8 ± 8.1 kg, age 23.2 ± 3.4 years), from a wide range of field-based sports, had sonographic images of their VL and MG musculature (for the dominant leg) recorded at rest before participating in a standardized maximal IMTP protocol. Results: Intraclass correlation coefficients (≥ 0.91, p < 0.001) and coefficient of variation percentages (≤ 2.5%) showed excellent reliability of the muscle structure and IMTP peak force measurements. A large positive relationship was found between VL muscle thickness and absolute IMTP peak force (r = 0.62, p < 0.01, power = 0.89). Moderate, but non-significant, relationships were observed between VL pennation angle and both absolute (r = 0.41, p = 0.06, power = 0.60) and relative (r = 0.39, p = 0.08, power = 0.46) IMTP peak force. A small non-significant correlation was noted between VL muscle thickness and relative IMTP peak force (r = 0.26, p = 0.19). No aspect of MG muscle structure was significantly correlated with IMTP peak force. Conclusion: The VL muscle thickness of male collegiate athletes’ dominant leg is largely correlated to their bilateral absolute IMTP peak force capacity (demonstrating 38% shared variance). Practitioners should, therefore, develop hypertrophy of male collegiate athletes’ VL musculature through appropriately designed strength training programs.

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