Robert Donatelli

Electromyographic Analysis of Core Trunk, Hip, and Thigh Muscles During 9 Rehabilitation Exercises

STUDY DESIGN Prospective, single-group, repeated-measures design. OBJECTIVE To identify exercises that could be used for strength development and the exercises that would be more appropriate for endurance or stabilization training. BACKGROUND The exercises analyzed are often used in rehabilitation programs for the spine, hip, and knee. They are active exercises using body weight for resistance; thus a clinician is unable to determine the amount of resistance being applied to a muscle group. Electromyographic (EMG) analysis can provide a measure of muscle activation so that the clinician can have a better idea about the effect the exercise may have on the muscle for strength, endurance, or stabilization. METHODS AND MEASURES Surface EMG analysis was carried out in 19 males and 11 females while performing the following 9 exercises: active hip abduction, bridge, unilateral-bridge, side-bridge, prone-bridge on the elbows and toes, quadruped arm/lower extremity lift, lateral step-up, standing lunge, and using the Dynamic Edge. The rectus abdominis, external oblique abdominis, longissimus thoracis, lumbar multifidus, gluteus maximus, gluteus medius, vastus medialis obliquus, and hamstring muscles were studied. RESULTS In healthy subjects, the lateral step-up and the lunge exercises produced EMG levels greater than 45% maximum voluntary isometric contraction (MVIC) in the vastus medialis obliquus, which suggests that they may be beneficial for strengthening that muscle. The side-bridge exercise could be used for strengthening the gluteus medius and the external oblique abdominis muscles, and the quadruped arm/lower extremity lift exercise may help strengthen the gluteus maximus muscle. All the other exercises produced EMG levels less than 45% MVIC, so they may be more beneficial for training endurance or stabilization in healthy subjects. CONCLUSION Our results suggest these exercises could be used for a core rehabilitation or performance enhancement program. Depending on the individual needs of a patient or athlete, some of the exercises may be more beneficial than others for achieving strength.

The evolution and mechanics of the midfoot and hindfoot

The foot and ankle have been an important part in the development of human gait and the erect posture of man. This paper presents several important evolutionary and biomechanical insights to the function of the midfoot and rearfoot. The bony architecture of the foot and ankle has enhanced the ability of man to walk in an upright posture. The complex movements of supination and pronation was established as a result of positional changes of the talus and calcaneus. The human foot has adapted to a bipedal striding gait by forming a compact structure that can absorb high ground reaction forces and provide a lever for push-off. Certain mechanical disorders of the foot and ankle may result from alterations of several evolutionary features. Excessive pronation and supination are the two major categories of mechanical disorders of the foot and ankle. The restoration of normal foot mechanics offers an important treatment approach to mechanical dysfunction of the foot and ankle.

Book Reviews: “Care of the Low Back”, “Manual for Functional Training”

CURRENT SCIENCE, VOL. 100, NO. 8, 25 APRIL 2011 1243 indicates that UV radiation is a component of DVM only among the UVsensitive daphnids inhabiting highly transparent waters. The next chapter is on the distribution of Daphnia. Experiments are described in the context of ideal free distribution and deep water chlorophyll maximum, but only to suggest future experiments. The sixth chapter on the parasites of daphnids enumerates a series of bacterial, fungal and protozoan parasites. By sequencing relevant recent information on epidemeiology, prevalence, horizontal and vertical distribution, modes of infection, spore survival, multiple infection, virulence, fitness and defences of the host, etc. the book has not left any area untouched. This chapter may prove useful to aquaculturists interested in the culture of live feed organisms, and traders and policy makers to frame laws for import and export of resting eggs/cysts (e.g. Artemia) of live feed organisms. Most interesting is the chapter concerning dormancy of durable ‘resting eggs’ in the context of dispersal, colonization, life-history strategies and bedhedging. The resting eggs of copepods are known to successfully hatch even after 350 years of dormancy, but the hatching success of the daphnids is limited to 50 years only. However, for reasons not yet known, <1% eggs alone hatch for every square metre area of sediments containing 2500 viable, dormant eggs of Daphnia galeata mendotae and 5000 eggs of D. pulicare. Incidentally, these values for the density (no./m) of resting eggs may be compared to 4000 and 122,000 eggs reported for the marine cladocerans Podon polyphemoides and Penilla avirostris respectively. That the DNA can be extracted from the dormant eggs of Daphnia and that its 200-yr-old epihippia can be used to trace environmental and anthropogenic changes induced on climate, acidification, eutrophication, pollution, etc. open totally new avenues for fascinating research. The last chapter on the genomic future informs the availability of complete genome of Daphnia pulex and sequencing of D. magna, which is in progress. It is heartening to know about the participation of 375 researchers from 19 countries in the Daphnia Genomics Consortium. With the ongoing interest in environmental genomics, the cladocerans have a lion’s share of 8% in the nearly 500,000 references in the ECOTOX database. With these developments, Daphnia shall certainly become a smart model organism for research in ecology and evolution. Lampert needs to be complimented for having comprehensively summarized relevant information citing 568 references from publications widely scattered in 120 journals, and 60-odd books. Yet a glaring omission is the total negligence/ ignorance of publications concerning tropical daphnids. It is rather unthinkable of a book, which neglects the Japanese contribution; Miyakawa et al. (2010) is the only Japanese publication cited in the book. Lampert could have much benefitted, had he referred to at least one review dedicated to O. Kinne on his 70th birthday. In keeping up with the excellent tradition of the series edited by Kinne, the book is a useful addition to biologists, limnologists and aquaculturists.