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.

While the general link between adolescent maltreatment and adolescent substance abuse is well established, questions remain regarding factors that may explain variability in the strength of this link. This study examines whether the link between maltreatment and substance abuse varies across three categories of maltreatment: physical, sexual and emotional. It also examines gender differences and timing of abuse (past or current). This study also examines the level of parental monitoring and what effect parental monitoring has on maltreated adolescents and their use of substances. Survey data were collected from six public schools in a rural Southwestern Oregon County on experience of maltreatment (emotional, physical and sexual) and use of substances (tobacco, alcohol and illicit drugs), gender differences and level of parental monitoring. Data were analyzed using t-tests and regression models. Results indicated that youth who currently experienced emotional, physical or sexual abuse were significantly more likely to use tobacco, alcohol, and illicit drugs than were youth who had experienced abuse in the past. They also indicated a significant interaction between gender and physical abuse, sexual abuse and emotional abuse (past and present combined) in predicting illicit drug use with males using illicit drugs at a significantly higher rate than females. As predicted, a significant interaction was found between parental monitoring and maltreatment/no maltreatment in predicting drug use. Maltreated youth with low levels of parental monitoring were significantly more likely to have high levels of substance use than were maltreated youth with high levels of parental monitoring. These results give rise to the need for further research into this subject to aid counselors in helping youth, especially male youth, in substance abuse treatment. Results of this study suggest a need for substance abuse treatment counselors to educate the parents of the treatment clients to closely monitor their adolescent as a possible means of reducing substance abuse. / Graduation date: 2002

Thesis (M. Soc. Sc.)--University of Hong Kong, 2006.

Thesis (Ph. D.)--Brigham Young University. Dept. of Marriage and Family Therapy, 2006. / Title of electronic copy: Relationship of implicit family process rules to adolescent presentation of psychological systems. Includes bibliographical references (p. 66-76).

Thesis (M.S.)--University of Delaware, 2006. / Principal faculty advisor: James E. Swasey, Dept. of Plant & Soil Sciences. Includes bibliographical references.

Thesis (M.S.W.)--University of Hong Kong, 2004.

Thesis (Ph. D.)--Lehigh University, 2000. / Includes vita. Includes bibliographical references (leaves 107-117).

Thesis, PlanB (M.S.)--University of Wisconsin--Stout, 1999. / Description based on microfiche version record. Includes bibliographical references.

Thesis (Ph. D.)--Open University. BLDSC no. DXN119979.

Thesis (Ph. D.)--University of Texas at Austin, 2001. / Vita. Includes bibliographical references. Available also from UMI/Dissertation Abstracts International.