The purpose of this study was to determine the correlation among three hand strength measurement methods: Hand dynamometer, MDD (Middle Digital Extension Isokinetic Dynamometer), and Cybex. Five students (2 males, 3 females) from Ball State University were asked to participate in this study. Both right and left lower arm data were collected from these subjects. A Cybex 340 (Lumax Cor.) was employed to determine wrist flexion and extension isokinetic peak torque, total work, and power at 30 degrees/second and 60 degrees/second. A MDD was used to determine third digit eccentric torque, work, and power. A hand dynamometer (Lafayette Instrument Co., Model 76618) was used to determine grip force. Pearson product moment correlation coefficients were used to determine correlation among these variables. Significant correlations were noted between isometric grip strength and isokinetic 30 and 60 degrees/second wrist flexion power, as well as between isometric grip strength and isokinetic 30 degrees/second wrist extensor power. The results of this study indicate there is very little relationship between the three clinically used measurement tools. / School of Physical Education

In the powerlifting deadlift, you use a grip where one hand is pronated and the other supinated. Earlier studies have noted differences in muscle activation between grips in upperbody excersices, but how the grip effects the muscle activation in the deadlift has not been investigated and it is not known if using the same grip over time can cause muscular imbalance or injuries. The purpose of the study was too is to investigate if there is a difference in force distribution and development between the left and right leg with a double pronated, dominant and non-dominant under-/overhand grip in the deadlift exercise. Subjects were 10 competitive powerlifters consisting of 7 men and 3 women. Testing was performed on two force plates measuring ground reaction force with one leg on each plate. The lifters did 2 lifts with each grip with 80% of their 1RM in the conventional deadlift. Peak force, time to peak force, force impulse and values at the same time as the total peak force was analyzed for each side. Peak force for the total force curve was also analyzed. The result showed one significant value between grips: The mean difference between the two sides at the same point as the total peak force showed a significans of P=0,02. Significant values were also found in force impulse (P=0,03) and values at total peak force (P=0,04) when analyzing lift one and two for the dominant grip between each other. This study shows that using the same over-/underhand grip does not affect force production or bilateral differences and is only a matter of comfort. However, it is hard to draw a conclusion and future testing should involve complementary methods to be able to state if there are differences and how these present themselves.

Thesis (Ph.D.)--University of Delaware, 2009. / Principal faculty advisor: Slobodan Jaric, Dept. of Health, Nutrition, & Exercise Sciences. Includes bibliographical references.

Doctor of Philosophy / The aims of the Thesis were: to investigate and quantify the factors influencing the production of maximum isometric grip strength force in a sample of Australian teenagers when using JamarTM-like handgrip dynamometers; to determine the reliability of this measure over long and short retest intervals; to establish a database of anthropometric and strength values for this group and prediction equations for premorbid strengths to aid assessment of recovery in those with upper limb pathologies. The history of these handgrip dynamometers demonstrates that they have been employed in one form or another for over three hundred years and are still widely used today in hand rehabilitation and medical examinations. Many new types of dynamometers have been constructed subsequent to the ubiquitous JamarTM and have all been briefly reviewed here. Handedness (dominance) was thought to be a possible factor influencing grip strength performance and was later evaluated. But first, the Edinburgh Handedness Inventory was tested with 658 teenagers and 64 adults and confirmed to be a valid tool for assessing handedness. Its validity was improved by substituting the tasks of sweeping and opening the lid of a box for hammering and use of a screwdriver. Its excellent reliability (ICC = .78, p < 0.01) was confirmed with 45 teenagers and 45 adults. There were 235 teenagers who performed maximal isometric grip strength tests and from the results a local database was created. It was confirmed that the grip strength difference in males and females becomes significant after the age of 13 years, and that the average teenaged male is stronger than the average teenaged female by 11.2 Kg force (p < .01). Height, weight, BMI, hand dimensions, past upper limb injuries, degrees of handedness and exercise levels were measured and compared with known norms to establish that the grip strength tested sample of teenagers was representative of urban teenagers in Australia. The influence of handedness on maximal grip strength in dominant and non-dominant hands was unable to be completely ascertained due to the vast majority of the sample of teenagers being right-handed. Only 13 of the 235 teenagers used their left hand for most tasks, with another 20 using their left hands for a small majority of tasks. There was a grip strength bias towards the dominant hand of 2.63 kg force (p < .01). The most accurate way to predict the grip strength of one hand is by knowing the grip strength of the other hand. Prediction models found that 90% (R2 adj .902) and 70% (R2adj .702) of the variance in one hand could be accounted for by the grip strength of their other hand for male and female teenagers, respectively. Prediction equations were also created to assist in estimating the pre-morbid grip strength of teenagers suffering from bilateral hand injuries. If for the males, measurements for height and hand surface area were entered into these models, the grip strength of the dominant and non-dominant hands could be estimated with 62.6 and 63.5% of the variance between the real and predicted scores accounted for, respectively. For the females the prediction models using height and hand surface area could only account for 33.9 and 42.8% of the variances, with no other independent variables improving the prediction equations. The reliability of the maximal grip strength performance of 154 of these teenagers was retested after one or four weeks. A number of sub-group permutations were created for age, gender, retest time interval and handedness groups. The measures of grip strength for males were highly reliable with ICC (3,1) values ranging from .91 to .97. These measures were significantly higher than that obtained from the females, where reliability values ranged from .69 to .83. Handedness played a significant part in grip strength reliability. The dominant hand of right-handed teenagers achieved an ICC (3,1) of .97, as contrasted with the non-dominant hand of left-handers who attained a very poor ICC (3,1) of .27. The shape of the hands of the males did not influence their grip strength or their reliability values, which ranged from .954 to .973. The shape of female hands did not affect their ability to generate maximal grip strength, only its reliability. The females with hands shaped squarer-than-average had mean grip strength reliability values of ICC (3,1) at only .48, in contrast to those with longer-than-average hands who achieved a mean ICC (3,1) of .92. The handle shape of the dynamometer may disadvantage square-handed females, and this should be further investigated.

Bakgrund: Även om kaströrelsen i detalj skiljer sig mellan olika idrotter så är den biomekaniska funktionen i grunden densamma. Inom alla kastrelaterade idrotter återkommer den så kallade accelerationsfasen, här har det visat sig att inåtrotationen i axelleden har en hög korrelation med bollhastighet i kaströrelsen. Axelledens inåtrotatorer har alltså en viktig funktion för ett effektivt kast. En funktionell uppvärmning av dessa strukturer optimerar prestationsförmågan och minskar skaderisken. Kan träningsredskapet Activation Grip (AG) effektivisera uppvärmningen av den övre extremiteten hos kastidrottare? Syfte: Att undersöka och jämföra hur muskelaktiviteten i m. pectoralis major (PM), m. deltoideus anterior (DA), m. flexor carpi raidalis (FCR) och m. extensor digitoris communis (EDC) påverkas vid inåtrotation i axelleden med och utan träningsredskapet AG. Studien syftar även till att utvärdera AG som produkt. Metod: Muskelaktiviteten i PM, DA, FCR och EDC registrerades med hjälp av elektromyografi (sEMG) hos 18 aktiva idrottare inom överarmskastrelaterade idrotter (ålder 23,7 ± 5,7) vid inåtrotation i axelleden med maximal hastighet, jämfört med samma rörelse med AG och 30% belastning. Resultat: Resultatet visade på en signifikant högre muskelaktivering (p &lt; 0.05) i DA, FCR, EDC under inåtrotationen med maximal hastighet. Hos PM sågs ingen signifikant skillnad i muskelaktivitet. AG fick över lag positiv respons från testdeltagarna.  Konklusion: Med resultatet i beaktande så skulle AG kunna kombineras tillsammans med andra uppvärmningsövningar för att få specifik aktivering i önskad muskulatur. Vidare studier gällande rörelse, motstånd och hastighet för att effektivisera användningen av AG bör göras. Även om AG fick positiv respons så bör produkten utvecklas ytterligare.

Thesis (M. Sc.)--York University, 2002. Graduate Programme in Kinesiology and Health Science. / Title on certificate page: Contributions of posture and force to forearm EMG during grip tasks. Typescript. Includes bibliographical references (leaves 108-119). Also available on the Internet. MODE OF ACCESS via web browser by entering the following URL: http://wwwlib.umi.com/cr/yorku/fullcit?pMQ71610.

Hand grip strength (HGS) is a new nutritional assessment parameter proposed by American Society for Parenteral and Enteral Nutrition (ASPEN) and the Academy of Nutrition and Dietetics (the Academy) for diagnosis of adult malnutrition related to acute illnesses, chronic diseases or starvation. Identification of ≥2 of the following conditions is considered to be malnourishment – weight loss, loss of muscle mass, loss of subcutaneous fat, fluid accumulation, diminished HGS and inadequate energy intake. HGS is also a marker of sarcopenia, a condition defined by low muscle mass and low muscle strength or performance, as identified by the European Working Group on Sarcopenia in Older People. It has also been shown that lower HGS is associated with deficits in activities of daily living (ADL) and mobility. HGS is emerging as an important screening tool especially in the malnourished and aging population. This research evaluates the applicability of HGS as a nutrition screening tool in long-term care older adults. Data from a total of 129 participants age ≥60 years involved in an ongoing walking program in long-term care facilities in Saskatoon available for analysis at the time this work was undertaken. Participants were randomly assigned for an intervention period of 16 weeks to one of three study groups: 1) Usual Care Group, 2) Interpersonal Interaction Group, and 3) Walking Program Group. Activity of daily living, cognition and depression scores and hand grip strength were recorded at baseline and every eight weeks. Information on vitamin D intake status prior to study commencement was also collected. This study provides values of low grip strength similar to those defined for the risk of sarcopenia in frail older adults. Stronger baseline HGS was correlated with greater ADL independence in females (B=0.079, P=0.044). Greater ability to eat at baseline was also associated with stronger grip in females when cognition status was taken into consideration. Baseline ADL (B=-0.024) and HGS (B=1.004) were significant predictors of subsequent ADL and HGS, respectively, in males (P<0.01). Baseline HGS was associated with subsequent ADL and HGS in females, but such association was modified by other covariates. In summary, if grip strength is to be used as a nutritional screening tool in long-term care facilities, dietitians shall be cautious of other factors such as the residents’ cognitive status and age and use in conjunction with other nutrition assessment methods.

Doctor of Philosophy / The aims of the Thesis were: to investigate and quantify the factors influencing the production of maximum isometric grip strength force in a sample of Australian teenagers when using JamarTM-like handgrip dynamometers; to determine the reliability of this measure over long and short retest intervals; to establish a database of anthropometric and strength values for this group and prediction equations for premorbid strengths to aid assessment of recovery in those with upper limb pathologies. The history of these handgrip dynamometers demonstrates that they have been employed in one form or another for over three hundred years and are still widely used today in hand rehabilitation and medical examinations. Many new types of dynamometers have been constructed subsequent to the ubiquitous JamarTM and have all been briefly reviewed here. Handedness (dominance) was thought to be a possible factor influencing grip strength performance and was later evaluated. But first, the Edinburgh Handedness Inventory was tested with 658 teenagers and 64 adults and confirmed to be a valid tool for assessing handedness. Its validity was improved by substituting the tasks of sweeping and opening the lid of a box for hammering and use of a screwdriver. Its excellent reliability (ICC = .78, p < 0.01) was confirmed with 45 teenagers and 45 adults. There were 235 teenagers who performed maximal isometric grip strength tests and from the results a local database was created. It was confirmed that the grip strength difference in males and females becomes significant after the age of 13 years, and that the average teenaged male is stronger than the average teenaged female by 11.2 Kg force (p < .01). Height, weight, BMI, hand dimensions, past upper limb injuries, degrees of handedness and exercise levels were measured and compared with known norms to establish that the grip strength tested sample of teenagers was representative of urban teenagers in Australia. The influence of handedness on maximal grip strength in dominant and non-dominant hands was unable to be completely ascertained due to the vast majority of the sample of teenagers being right-handed. Only 13 of the 235 teenagers used their left hand for most tasks, with another 20 using their left hands for a small majority of tasks. There was a grip strength bias towards the dominant hand of 2.63 kg force (p < .01). The most accurate way to predict the grip strength of one hand is by knowing the grip strength of the other hand. Prediction models found that 90% (R2 adj .902) and 70% (R2adj .702) of the variance in one hand could be accounted for by the grip strength of their other hand for male and female teenagers, respectively. Prediction equations were also created to assist in estimating the pre-morbid grip strength of teenagers suffering from bilateral hand injuries. If for the males, measurements for height and hand surface area were entered into these models, the grip strength of the dominant and non-dominant hands could be estimated with 62.6 and 63.5% of the variance between the real and predicted scores accounted for, respectively. For the females the prediction models using height and hand surface area could only account for 33.9 and 42.8% of the variances, with no other independent variables improving the prediction equations. The reliability of the maximal grip strength performance of 154 of these teenagers was retested after one or four weeks. A number of sub-group permutations were created for age, gender, retest time interval and handedness groups. The measures of grip strength for males were highly reliable with ICC (3,1) values ranging from .91 to .97. These measures were significantly higher than that obtained from the females, where reliability values ranged from .69 to .83. Handedness played a significant part in grip strength reliability. The dominant hand of right-handed teenagers achieved an ICC (3,1) of .97, as contrasted with the non-dominant hand of left-handers who attained a very poor ICC (3,1) of .27. The shape of the hands of the males did not influence their grip strength or their reliability values, which ranged from .954 to .973. The shape of female hands did not affect their ability to generate maximal grip strength, only its reliability. The females with hands shaped squarer-than-average had mean grip strength reliability values of ICC (3,1) at only .48, in contrast to those with longer-than-average hands who achieved a mean ICC (3,1) of .92. The handle shape of the dynamometer may disadvantage square-handed females, and this should be further investigated.

Thesis (Ph. D.)--West Virginia University, 2006. / Title from document title page. Document formatted into pages; contains xiii, 138 p. : ill. (some col.). Vita. Includes abstract. Includes bibliographical references (p. 112-110).

Thesis (M.S.)--Slippery Rock University, 2002. / Includes bibliographical references (leaves 39-41).