Ola Eriksrud and his colleagues recently published the first study showing the reliability and validity of a hand reach-based movement assessment. Their test will allow researchers and coaches to explore the relationship between dynamic postural control, balance and functional mobility of whole-body movements in athletic development, rehabilitation and injury prevention.
Nearly every upper extremity movement in sports is the end result of whole body movement across multiple planes of motion. From the instant an athlete attains his preparatory stance to the release of the ball, contact of the punch or follow-through of the racquet the athlete creates energy through his lower body and trunk before funneling it through the shoulder to achieve the end result.
Most functional mobility tests only study a small, isolated part of the kinetic chain. Individual joint testing does not capture neuromuscular control or the interrelationships between muscles. Many movement screens narrowly focus on the sagittal and frontal planes of motion, either in isolation or together, but always excluding the transverse plane. They often tend to be subjective, as well. And foot reach tests only measure lower extremity movement and control, but do not investigate anything at the arms.
Ola Eriksrud developed a hand reach-based assessment tool to address these short-comings. He and his colleagues from the Norwegian School of Sport Science and the University of Innsbruck (Austria) recently published the first validity and reliability study using this tool.
Eriksrud based the protocol on the star excursion balance test (SEBT), and called it the hand reach star excursion balance test (HSEBT). The HSEBT consists of 10 hand reaches while standing on one foot (stance foot) with toe-touch of the other foot, mirroring the 8 foot reaches in a SEBT with the addition of two rotational reaches. Subjects perform the HSEBT while standing at the center of a 1080 MAP testing mat. This provides quantitative, objective and reliable data on the athlete’s movement, which the tester complements with his subjective observation as well as feedback from the subject.
By having their subjects reach beyond arm’s length in and across all planes of motion, the HSEBT accounts for dynamic postural control, balance, strength and mobility. The rotational reaches are particularly important for understanding the relationship between mobility and power in upper extremity sports.
“In any power sport – foot or hand – you get the greatest speed via the transverse plane,” Eriksrud said. “The shoulder itself is incapable of generating the angular speeds you see in sports, for example. The energy comes from somewhere else, and the shoulder adds a little bit to the fire. The HSEBT is a step towards capturing what is important across the entire kinetic chain leading to the key moment in a sport.”
One part of research is the relationship between mobility and sport performance measures. Eriksrud and Ali Ghelem produced a case study in 2014 showing how improved mobility tracked with increased power in a professional golfer. The golfer began his training with low back pain, shoulder pain and limited hip mobility. Pre- and post- testing with the HSEBT illustrated his mobility improvements in tandem with strength and power training.
Eriksrud is particularly interested in determining the role of “movement reserve” in sports performance and injury prevention. The absolute amount of joint movement in a sport may be less of a risk factor than where it occurs relative to the maximum range of motion.
“How much of your maximum mobility do you utilize in your sport? If you have less mobility, you are closer to the minimum necessary for a given level of performance and you are at a greater percentage of your maximum. Movement has a threshold as does any metabolic or output system. Give yourself a buffer between what is necessary and what you are capable of producing.”
Eriksrud’s team has developed 104 tests so far. Eriksrud has other manuscripts in preparation, expanding the validity and application of the HSEBT for assessment, performance and rehabilitation. The HSEBT is one component of the 1080 MAP. Over time, the 1080 MAP and its battery of tests will shed light on the relationship between mobility and sports performance. “There will be changes, reductions and additions,” Eriksrud promises. “The empirical evidence will determine development.”
Download the study from Journal of Functional Morphology and Kinesiology:
Eriksrud, O.; Federolf, P.; Sæland, F.; Litsos, S.; Cabri, J. Reliability and Validity of the Hand Reach Star Excursion Balance Test. J. Funct. Morphol. Kinesiol. 2017, 2, 28. (Full text and PDF)