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Biomedical subjects

W L Westcott

Publications and source records attributed to W L Westcott.

6 recordsLinked to original sources
PubMed2001

Effects of regular and slow speed resistance training on muscle strength.

BACKGROUND: The study assessed a way to increase the intensity and effectiveness of resistance training by comparing training with a slower repetition speed to training with a conventional repetition speed. Slower repetition speed may effectively increase intensity throughout the lifting phase while decreasing momentum. METHODS: Two studies were done with untrained men (N=65) and women (N=82), (mean age=53.6) who trained two to three times per week for eight to 10 weeks on a 13 exercise Nautilus circuit performing one set of each exercise. Participants exclusively trained using regular speed repetitions for 8 to 12 repetitions per set at 7 sec each (2 sec lifting, 1 sec pause, 4 sec lowering) or a Super Slow training protocol where they completed 4 to 6 repetitions per set at 14 sec each (10 sec lifting, 4 sec lowering). All of the participants were tested for either the 10 repetition-maximum (RM) weightload (regular-speed group) or the 5-RM weightload (slow-speed group). RESULTS: In both studies, Super-Slow training resulted in about a 50% greater increase (p<0.001) in strength for both men and women than regular speed training. In Study 1, the Super-Slow training group showed a mean increase of 12.0 kg and the regular speed group showed an increase of 8.0 kg increase (p<0.001). In Study 2, the Super-Slow training group showed a 10.9 kg increase and the regular speed group showed an increase of 7.1 kg (p<0.001). CONCLUSIONS: Super-Slow training is an effective method for middle-aged and older adults to increase strength. Although studies still need to be done with at-risk populations, repetition speed should be considered when prescribing resistance training.

Adult↗
PubMed2001

Effects of different resistance training protocols on upper-body strength and endurance development in children.

This study examined the effects of 4 different resistance training protocols on upper-body strength and local muscle endurance development in children. Untrained boys and girls (mean +/- SD age, 8.1 +/- 1.6 years) trained twice per week for 8 weeks using child-sized weight machines and medicine balls weighing 1-2.5 kg. In addition to general conditioning exercises, subjects in each exercise group performed 1 set of the following exercise protocols for upper-body conditioning: 6-8 repetitions with a heavy load on the chest press exercise (HL, n = 15); 13-15 repetitions with a moderate load on the chest press exercise (ML, n = 16); 6-8 repetitions with a heavy load on the chest press exercise immediately followed by 6-8 medicine ball chest passes (CX, n = 12); or 13-15 medicine ball chest passes (MB, n = 11). Twelve children served as nontraining controls (CT). After training, only the ML and CX groups demonstrated significant (p < 0.05) improvements in 1RM chest press strength (16.8% and 16.3%, respectively) as compared with the CT group. Local muscle endurance, as determined by the number of repetitions performed posttraining on the chest press exercise with the pretraining 1RM load, significantly increased in the ML group (5.9 +/- 3.2 repetitions) and CX group (5.2 +/- 3.6 repetitions) as compared with the CT group. In terms of enhancing the upper-body strength and local muscle endurance of untrained children, these findings favor the prescription of higher-repetition training protocols during the initial adaptation period.

Adaptation, Physiological↗
PubMed1999

The effects of different resistance training protocols on muscular strength and endurance development in children.

BACKGROUND: Previous research has shown that children can increase their muscular strength and muscular endurance as a result of regular participation in a progressive resistance training program. However, the most effective exercise prescription regarding the number of repetitions remains questionable. OBJECTIVE: To compare the effects of a low repetition-heavy load resistance training program and a high repetition-moderate load resistance training program on the development of muscular strength and muscular endurance in children. Design. Prospective, controlled trial. SETTING: Community-based youth fitness center. SUBJECTS: Eleven girls and 32 boys between the ages of 5.2 and 11.8 years. INTERVENTION: In twice-weekly sessions of resistance training for 8 weeks, children performed 1 set of 6 to 8 repetitions with a heavy load (n = 15) or 1 set of 13 to 15 repetitions with a moderate load (n = 16) on child-size exercise machines. Children in the control group (n = 12) did not resistance train. One repetition maximum (RM) strength and muscular endurance (repetitions performed posttraining with the pretraining 1-RM load) were determined on the leg extension and chest press exercises. RESULTS: One RM leg extension strength significantly increased in both exercise groups compared with that in the control subjects. Increases of 31.0% and 40.9%, respectively, for the low repetition-heavy load and high repetition-moderate load groups were observed. Leg extension muscular endurance significantly increased in both exercise groups compared with that in the control subjects, although gains resulting from high repetition-moderate load training (13.1 +/- 6.2 repetitions) were significantly greater than those resulting from low repetition-heavy load training (8.7 +/- 2.9 repetitions). On the chest press exercise, only the high repetition-moderate load exercise group made gains in 1-RM strength (16.3%) and muscular endurance (5.2 +/- 3.6 repetitions) that were significantly greater than gains in the control subjects. CONCLUSION: These findings support the concept that muscular strength and muscular endurance can be improved during the childhood years and favor the prescription of higher repetition-moderate load resistance training programs during the initial adaptation period.

Analysis of Variance↗
PubMed1992

Strength and bite, Part 2: Testing isometric strength using a MORA set to a functional criterion.

The effect on isometric strength of biting on three intraoral devices and habitual occlusion was analyzed. Only subjects who showed a relative weakness to the Isometric Deltoid Press (IDP) when biting as opposed to maintaining the mandible in an unsupported rest position were included in the study. Both in the original 35 subjects and the 23 subjects returning on the second day, performance wearing the appliance set by a functional criterion of peak strength (locking) to the IDP was significantly greater than wearing a placebo appliance and a bite raising appliance that deflected the mandible 1 mm to the left. Strength biting on the appliance set by a functional criterion was significantly greater than all these conditions. Strength biting in habitual trials that were matched with the deflection condition was found to be significantly greater than that biting in the placebo condition. It was concluded that a relationship does exist between bite and isometric strength. Previous speculation about the role of placebo effect was not substantiated by the data gathered in this experiment.

Adolescent↗
PubMed1991

Strength and bite, Part 1: An analytical review.

The original clinical observations and research in the area of bite and strength enhancement studied individuals with obvious malocclusion and a subject population with mixed occlusions. An increase in isometric strength was obtained when biting on a K-MORA, an intraoral device that supports a mandibular position determined by a functional criterion. The criterion is a locking response to the Isometric Deltoid Press, a muscle challenge used by kinesiologists. Rather than replication with improved design, subsequent research (1) employed different mandibular positions based on therapeutic, electrical impulse or structural criteria; (2) tested mainly isokinetic strength; (3) referred to "strength" without qualification, implying more generalization than the findings actually allowed; (4) criticized and rejected positive findings by attributing strength increase to the placebo effect even though in no instance has the placebo effect been demonstrated in this field. Considering published and unpublished research on isometric strength and the irrelevance of many studies that found no difference in isokinetic strength, it is concluded that it is most probable that isometric strength is increased by the K-MORA in mixed populations.

Bite Force↗