Levels of Muscle Activation in Strength and Conditioning Exercises and Dynamometer Hiking in Junior Sailors

Abstract

Although strength and conditioning exercises have been prescribed to enhance performance and prevent injury in sailors, little is known about these exercises in comparison to the demands placed on the sailor's musculature while hiking maximally. Because of the difficulty in collecting hiking-related data on water, a 3-minute maximal hiking test (HM180) has been previously developed for use in the laboratory setting. There were 2 aims of this study. The first aim was to determine whether discriminative validity could be shown for the HM180 test in a group of junior sailors of differing ability level and gender. The second aim was to determine whether differences in muscle activation existed between selected strength and conditioning exercises and the HM180 test. Twenty-nine adolescent boy and girl sailors aged between 14 and 16 years from the Singaporean National Byte Class training squad (n = 12) and the Singapore High Participation Group (n = 17) were recruited for this study. The average levels of normalized muscle activation in selected lower limb and trunk muscles in 4 selected strength and conditioning exercises (leg extension, back squat, and back extension exercises, a 30-second hiking hold) and a maximal 3-minute hiking test (the HM180 test) were quantified. Discriminative validity of the HM180 test was shown, and it was confirmed that the strength and conditioning exercises provide an overload stimulus for the HM180 test. Further, similar levels of muscle activation were found for the vastus lateralis in the leg extension and back squat exercises, and the superficial lumbar multifidus in the back extension and back squat exercises. This study has the potential to inform the design of strength and conditioning programs for junior sailors.

A prospective study on dinghy sailors’ training habits and injury incidence with a comparison between elite sailor and club sailor during a 12-month period

“…However, physical training will ensure that sailors can tolerate the physical requirements and in this way become better sailors; but, if, for example, the strength training is not performed correctly, it can lead to injuries 25. Having a strength and conditioning coach who has knowledge in how to design and individualise training programmes is suggested to be of importance for injury prevention 10 26 27. One concern is that only 36% of the sailors had help from a strength and conditioning coach.…”

“…This position, hiking, is the most strenuous when sailing up-wind 6 7. Hiking requires largely static activity in the knee extensors and both static and dynamic actions in the abdominals and the hip flexors 2 9 10. It also significantly reduces the blood-flow in the legs due to the sustained isometric contraction of the quadriceps 1 5.…”

Normalization of EMG Signals: To Normalize or Not to Normalize and What to Normalize to?

“…• trunk flexion, hips and knees flexed to 90°, feet supported, trunk in full flexion (supine) [35,36] • trunk flexion, legs bent at 45°,and secured, trunk position not mentioned (supine) [37] internal oblique • trunk flexion and lateral flexion, hips and knees flexed to 90°, feet supported, trunk in full flexion and rotated contra-laterally (supine) [35] • trunk flexion and lateral flexion, hips and knees flexed to 90°, feet supported, trunk in full flexion and rotated ipsi-laterally (supine) [36] gluteus maximus • hip extension, hip flexed 45° (prone) [38] • back extension, hip flexed 30° (seated) [39] • hip abduction at 10° abduction, leg fully extended (side lying) contra-lateral knee and hip flexed 30° [40] gluteus medius…”

“…• knee extension, knee flexed 90°, hip flexed 90° (sitting) [38,43] • knee extension, knee flexed 60°, hip flexed 90° (sitting) [44,45] • knee extension, knee flexed 45° (sitting) [37] vastus medialis • knee extension, knee flexed 60° (sitting) [44,45] • knee extension, knee flexed 90°, hip flexed 90° (sitting) [43] rectus femoris • knee extension, knee flexed 90°, hip flexed 80° to 90° (sitting) [35,36,38,43] • knee extension, knee flexed 60°, hip flexed 90° (sitting) [44][45][46] lateral hamstring (biceps femoris) long head…”

“…• knee flexion, knee flexed 90°, hip flexed 90° (sitting) [38] • knee flexion, knee flexed 60° (sitting) [44,46] • knee flexion, knee flexed 60° (prone) [45] • knee flexion, knee flexed 90°, hands clasped behind head (prone) [37] gastrocnemius lateralis…”