Papers by Tracey Matthews
Journal of Sports Science Medicine, 2012
Interval and circuit weight training are popular training methods for maximizing time-efficiency,... more Interval and circuit weight training are popular training methods for maximizing time-efficiency, and are purported to deliver greater physiological benefits faster than traditional training methods. Adding interval training into a circuit weight-training workout may further enhance the benefits of circuit weight training by placing increased demands upon the cardiovascular system. Our purpose was to compare acute effects of three circuit weight training protocols 1) traditional circuit weight training, 2) aerobic circuit weight training, and 3) combined circuit weight-interval training on blood lactate (BLA), heart rate (HR), and ratings of perceived exertion (RPE). Eleven recreationally active women completed 7 exercise sessions. Session 1 included measurements of height, weight, estimated VO2max, and 13 repetition maximum (RM) testing of the weight exercises. Sessions 2-4 were held on non-consecutive days for familiarization with traditional circuit weight training (TRAD), aerobic circuit weight training (ACWT), and combined circuit weight-interval training (CWIT) protocols. In sessions 5-7, TRAD, ACWT, and CWIT were performed in a randomized order ≥ 72 hr apart for measures of BLA, HR, and RPE at pre-exercise and following each of three mini-circuit weight training stations. Repeated-measures ANOVAs yielded significant interactions (p < 0.05) in BLA, HR, and RPE. Combined circuit weight-interval training (CWIT) produced higher BLA (7.31 ± 0.37 vs. TRAD: 3.99 ± 0.26, ACWT: 4.54 ± 0.31 mmol.L(-1)), HR (83.51 ± 1.18 vs. TRAD: 70.42 ± 1.67, ACWT: 74.13 ± 1.43 beats.min(-1)) and RPE (8.14 ± 0.41 vs. TRAD: 5.06 ± 0.43, ACWT: 6.15 ± 0.42) at all measures. Aerobic circuit weight training (ACWT) elicited greater RPE than traditional circuit weight training (TRAD) at all measures. Including combined circuit weight-interval training (CWIT) workouts into exercise programming may enhance fitness benefits and maximize time-efficiency more so than traditional circuit training methods.
Medicine and science in sports and exercise
PURPOSE: The purpose of this study was to investigate the effects of 6 weeks of betaine supplemen... more PURPOSE: The purpose of this study was to investigate the effects of 6 weeks of betaine supplementation on strength, body composition, and homocysteine thiolactone (HCTL) in experienced strength trained men.METHODS: Twenty-three subjects were matched for training experience (4.8 + 2.3 years) and body fat percentage (BF%: 16.9 + 8.0%), randomly assigned to either a placebo (PL; n = 12) or betaine group (BET; n = 11; 2.5 g/day), and completed a 6 week periodized training program consisting of 3 two-week micro-cycles. Bench press and back squat training volumes were recorded and changes in training volume were assessed at each micro-cycle. Fasting urine was collected at baseline (BL), weeks 2, 4 and 6, and assayed for HCTL. Subjects were tested prior to and following 6 weeks of treatment. Arm and thigh cross sectional area (CSA) was estimated as described by Moratani and DeVries (1979). Body density was estimated via skin fold calipers and used to estimate BF%, fat mass (FM), and lean ...
Journal of sports science & medicine
The present study compared the metabolic responses between a single low-carbohydrate (LC) and low... more The present study compared the metabolic responses between a single low-carbohydrate (LC) and low-fat (LF) meal followed by an aerobic exercise bout in females. Subjects included 8 active, premenopausal females. Subjects completed a LC and LF testing session. Respiratory gas exchange (RER) measurements were taken for 20 min fasted, for 55 min postprandial (PP), and during 30 min of exercise. Blood was collected for assessment of glucose (G), insulin (IN), triglycerides (TG), and free fatty acids (FFA) during the final 10 min of each time period. The LF meal provided 396 kcal (78% carbohydrate, 7% fat, and 15% protein). The LC meal provided 392 kcal (15% carbohydrate, 68% fat, and 18% protein). No significant differences existed between test meals for fasting blood measurements. PP IN (μU·mL(-1)) levels were significantly lower following LC compared to LF [10.7 (6.1) vs. 26.0 (21.0)]. Postexercise (PE) FFA (mEq·L(-1)) levels were significantly greater following LC [1.1 (0.3) vs. 0.5 ...
The Journal of Strength and Conditioning Research
Previous research has found that net joint moments (NJM) at the hip, knee and ankle do not increa... more Previous research has found that net joint moments (NJM) at the hip, knee and ankle do not increase uniformly as relative intensity increases during 90 degree squats from 25-100% 1 RM. As squats are typically performed to a parallel depth, it is important to understand if the same is true for parallel squats. Further, it is important to understand how NJM change across a narrow relative intensity range. Purpose: To evaluate how increasing relative intensity affects lower extremity net joint moments during parallel squats in men and women during parallel squats. Methods: Two men and two women experienced with the high-bar back squat performed sets of 3 repetitions at 50%, 60%, 70%, 80% and 90% 1 RM. Retro-reflective markers in a 6-degree of freedom configuration were recorded by a 9-camera optoelectronic motion capture system sampling at 120Hz and force platform data were collected simultaneously at 1200Hz. Peak sagittal plane NJM for the hip extensors, knee extensors, and ankle plantar-flexors during the concentric (ascending) phase of the squat were calculated using inverse dynamics. NJM at each joint were normalized to the maximum peak NJM attained (i.e. across all loads) for that joint and expressed as a percentage (i.e. 100% is the maximum NJM developed at the joint). Data were averaged across participants and plotted against relative intensity. The relation between relative intensity and peak NJM of the hip extensors, knee extensors and ankle plantar-flexors was determined using regression analyses. Results: Knee extensor NJM was high for all relative intensities (.87%). In contrast, ankle plantar-flexor (67%) and hip extensor (69%) NJM were low at the lowest relative intensity. Ankle plantar-flexor (R 2 =0.98) and hip extensor (R 2 =0.97) NJM increased in a linear fashion with increasing relative intensity. Knee extensor NJM, however, did not follow a linear trend (R 2 =0.37). Rather, the relation of knee extensor NJM to relative intensity was best approximated by a second order polynomial (R 2 =0.80), with peak NJM reaching a maximum at 80% 1 RM and declining at 90% 1 RM. Conclusion: Results suggest that torque generation of the knee extensors reached their maximal ability to contribute to squatting performance at low relative intensities, whereas the hip extensors and ankle-plantar flexors were operating sub-maximally. These data are indicative of the control strategy used to allow individuals to lift heavier external loads. Practical Applications: Understanding multi-joint control mechanisms with respect to mechanical stimuli are pertinent for designing appropriate training programs. Even at low relative intensities, the squat is a favourable exercise for improving knee extensor strength, whereas heavier loads increase the demand on the hip extensor and ankle plantar-flexor musculature. However, the use of excessive loads may decrease knee extensor demand, therefore reducing the effectiveness of the squat for training this muscle group. Acknowledgement:
The Journal of Strength and Conditioning Research
Previous research has found that net joint moments (NJM) at the hip, knee and ankle do not increa... more Previous research has found that net joint moments (NJM) at the hip, knee and ankle do not increase uniformly as relative intensity increases during 90 degree squats from 25-100% 1 RM. As squats are typically performed to a parallel depth, it is important to understand if the same is true for parallel squats. Further, it is important to understand how NJM change across a narrow relative intensity range. Purpose: To evaluate how increasing relative intensity affects lower extremity net joint moments during parallel squats in men and women during parallel squats. Methods: Two men and two women experienced with the high-bar back squat performed sets of 3 repetitions at 50%, 60%, 70%, 80% and 90% 1 RM. Retro-reflective markers in a 6-degree of freedom configuration were recorded by a 9-camera optoelectronic motion capture system sampling at 120Hz and force platform data were collected simultaneously at 1200Hz. Peak sagittal plane NJM for the hip extensors, knee extensors, and ankle plantar-flexors during the concentric (ascending) phase of the squat were calculated using inverse dynamics. NJM at each joint were normalized to the maximum peak NJM attained (i.e. across all loads) for that joint and expressed as a percentage (i.e. 100% is the maximum NJM developed at the joint). Data were averaged across participants and plotted against relative intensity. The relation between relative intensity and peak NJM of the hip extensors, knee extensors and ankle plantar-flexors was determined using regression analyses. Results: Knee extensor NJM was high for all relative intensities (.87%). In contrast, ankle plantar-flexor (67%) and hip extensor (69%) NJM were low at the lowest relative intensity. Ankle plantar-flexor (R 2 =0.98) and hip extensor (R 2 =0.97) NJM increased in a linear fashion with increasing relative intensity. Knee extensor NJM, however, did not follow a linear trend (R 2 =0.37). Rather, the relation of knee extensor NJM to relative intensity was best approximated by a second order polynomial (R 2 =0.80), with peak NJM reaching a maximum at 80% 1 RM and declining at 90% 1 RM. Conclusion: Results suggest that torque generation of the knee extensors reached their maximal ability to contribute to squatting performance at low relative intensities, whereas the hip extensors and ankle-plantar flexors were operating sub-maximally. These data are indicative of the control strategy used to allow individuals to lift heavier external loads. Practical Applications: Understanding multi-joint control mechanisms with respect to mechanical stimuli are pertinent for designing appropriate training programs. Even at low relative intensities, the squat is a favourable exercise for improving knee extensor strength, whereas heavier loads increase the demand on the hip extensor and ankle plantar-flexor musculature. However, the use of excessive loads may decrease knee extensor demand, therefore reducing the effectiveness of the squat for training this muscle group. Acknowledgement:
The Journal of Strength and Conditioning Research
Interval and circuit weight training are popular training methods for maximizing time-efficiency,... more Interval and circuit weight training are popular training methods for maximizing time-efficiency, and are purported to deliver greater physiological benefits faster than traditional training methods. Adding interval training into a circuit weight-training workout may further enhance the benefits of circuit weight training by placing increased demands upon the cardiovascular system. Our purpose was to compare acute effects of three circuit weight training protocols 1) traditional circuit weight training, 2) aerobic circuit weight training, and 3) combined circuit weight-interval training on blood lactate (BLA), heart rate (HR), and ratings of perceived exertion (RPE). Eleven recreationally active women completed 7 exercise sessions. Session 1 included measurements of height, weight, estimated VO 2max , and 13 repetition maximum (RM) testing of the weight exercises. Sessions 2-4 were held on non-consecutive days for familiarization with traditional circuit weight training (TRAD), aerobic circuit weight training (ACWT), and combined circuit weight-interval training (CWIT) protocols. In sessions 5-7, TRAD, ACWT, and CWIT were performed in a randomized order ≥ 72 hr apart for measures of BLA, HR, and RPE at preexercise and following each of three mini-circuit weight training stations. Repeated-measures ANOVAs yielded significant interactions (p < 0.05) in BLA, HR, and RPE. Combined circuit weight-interval training (CWIT) produced higher BLA (7.31 ± 0.37 vs. TRAD: 3.99 ± 0.26, ACWT: 4.54 ± 0.31 mmol . L -1 ), HR (83.51 ± 1.18 vs. TRAD: 70.42 ± 1.67, ACWT: 74.13 ± 1.43 beats . min -1 ) and RPE (8.14 ± 0.41 vs. TRAD: 5.06 ± 0.43, ACWT: 6.15 ± 0.42) at all measures. Aerobic circuit weight training (ACWT) elicited greater RPE than traditional circuit weight training (TRAD) at all measures. Including combined circuit weight-interval training (CWIT) workouts into exercise programming may enhance fitness benefits and maximize timeefficiency more so than traditional circuit training methods.
Journal of athletic training, 1999
To examine differences in anterior tibial translation (ATT) among sports, sex, and leg dominance ... more To examine differences in anterior tibial translation (ATT) among sports, sex, and leg dominance in collegiate athletes with normal anterior cruciate ligament integrity. Subjects from various athletic teams were measured for ATT in right and left knees. Sixty subjects were measured for ATT with a KT-1000 knee arthrometer. Statistical analyses were computed for each sex and included a 2 x 3 x 4 mixed-factorial analysis of variance (ANOVA) for anterior cruciate ligament displacement, right and left sides, and force and sport. A 2 x 2 x 3 mixed-factorial ANOVA was computed to compare means for sex and force. A 2 x 3 mixed-factorial ANOVA was computed to compare sex differences across 3 forces. For males and females, no significant interactions were found among leg, force, and sport for mean ATT, for leg and sport or leg and force, or for translation values between dominant and nondominant legs. Males had a significant interaction for force and sport, and a significant difference was fo...
Journal of athletic training, 2004
OBJECTIVE: To compare the effect of creatine supplementation on thermoregulation in males and fem... more OBJECTIVE: To compare the effect of creatine supplementation on thermoregulation in males and females during exercise in a thermoneutral environment. DESIGN AND SETTING: Male and female subjects participated in 30 minutes of cycle ergometry in nonsupplemented (NS) and creatine-supplemented (Cr) conditions at 70% to 75% of predetermined peak oxygen consumption. SUBJECTS: Ten male and ten female subjects were evaluated with and without creatine supplementation. MEASUREMENTS: Analyses were performed during exercise for core temperature and mean skin temperature using two 2 x 2 x 7 mixed-factorial analyses of variance (ANOVAs). We compared mean differences between NS and Cr conditions and sex for heart rate, systolic blood pressure, and diastolic blood pressure using 3 2 x 2 x 4 mixed-factorial ANOVAs. Three 2 x 2 mixed-factorial ANOVAs were computed to examine differences between sex and conditions for the following variables: nude body weight and blood urea nitrogen before and after e...
Journal of athletic training, 2001
OBJECTIVE: To compare the differences in the concentric hamstrings:quadriceps (H:Q) ratio among a... more OBJECTIVE: To compare the differences in the concentric hamstrings:quadriceps (H:Q) ratio among athletes in different sports at 3 velocities. DESIGN AND SETTING: We measured the H:Q ratio of both knees using the Biodex Pro Isokinetic Device. SUBJECTS: Eighty-one male and female collegiate athletes. MEASUREMENTS: We performed analyses for sport, velocity, and side of body for each sex. To compare the means of the concentric H:Q ratios for mean peak torque and mean total work, a 2 x 3 x 4 mixed-factorial analysis of variance was computed for women and a 2 x 2 x 3 mixed-factorial analysis of variance was computed for men. RESULTS: We observed no significant interactions for men and women for the concentric H:Q ratio for mean peak torque. There was a significant mean difference among velocity conditions and a significant difference for men with respect to velocity. No significant differences were found for side of body or sport. CONCLUSIONS: The H:Q ratio increased as velocity increased...
Journal of sports science & medicine, 2009
The purpose of this investigation was to determine if creatine supplementation assisted with redu... more The purpose of this investigation was to determine if creatine supplementation assisted with reducing the amount of exercise induced muscle damage and if creatine supplementation aided in recovery from exercise induced muscle damage. Two groups of subjects (group 1 = creatine; group 2 = placebo) participated in an eccentric exercise protocol following 7 and 30 days of creatine or placebo supplementation (20 g.d(-1) for 7 d followed by 6g.d(-1) for 23 d = 30 d). Prior to the supplementation period, measurements were obtained for maximal dynamic strength, maximal isometric force, knee range of motion, muscle soreness, and serum levels of creatine kinase (CK) and lactate dehydrogenase (LDH). Following 7 days of creatine supplementation, on day 8, subjects began consuming 6 g.d(-1) of creatine for 23 days. Additionally on days 8 and 31, subjects performed an eccentric exercise protocol using the knee extensors to induce muscle damage. Indirect markers of muscle damage, including maximal...
Journal of sports science & medicine, 2012
Interval and circuit weight training are popular training methods for maximizing time-efficiency,... more Interval and circuit weight training are popular training methods for maximizing time-efficiency, and are purported to deliver greater physiological benefits faster than traditional training methods. Adding interval training into a circuit weight-training workout may further enhance the benefits of circuit weight training by placing increased demands upon the cardiovascular system. Our purpose was to compare acute effects of three circuit weight training protocols 1) traditional circuit weight training, 2) aerobic circuit weight training, and 3) combined circuit weight-interval training on blood lactate (BLA), heart rate (HR), and ratings of perceived exertion (RPE). Eleven recreationally active women completed 7 exercise sessions. Session 1 included measurements of height, weight, estimated VO2max, and 13 repetition maximum (RM) testing of the weight exercises. Sessions 2-4 were held on non-consecutive days for familiarization with traditional circuit weight training (TRAD), aerobi...
Metabolic syndrome and related disorders, 2012
Preserving fat-free mass (FFM) during weight loss is important in older adults. The purpose was t... more Preserving fat-free mass (FFM) during weight loss is important in older adults. The purpose was to examine a low-fat diet (LFD) versus a carbohydrate-restricted diet (CRD) with and without progressive resistance exercise (PRE) on preservation of FFM in older men with metabolic syndrome. A total of 42 men (59±7 years) were matched [body mass index (BMI)] and randomized to LFD, LFD&PRE, CRD, and CRD&PRE. PRE groups performed supervised strength training three times per week. Body weight, composition, metabolic syndrome criteria, and strength were measured at baseline and week 12. A 3-day diet record was kept at baseline and at weeks 1, 6, and 12. Attrition (24%) was similar between groups. Depicted as % carbohydrate:fat:protein, the intervention diet was: LFD=55:24:18, LFD&PRE=57:20:20, CRD=16:54:28, and CRD&PRE=12:56:31. Weight (lb) decreased similarly in all groups (LFD, -18.0±7.4; LFD&PRE, -19.8±12.8; CRD, -20.2±8.0; CRD&PRE, -22.7±6.0; P<0.001), and number of participants with ...
Medicine & Science in Sports & Exercise, 1999
Medicine & Science in Sports & Exercise, 2009
Medicine & Science in Sports & Exercise, 2010
Medicine & Science in Sports & Exercise, 2003
Medicine & Science in Sports & Exercise, 2009
Medicine & Science in Sports & Exercise, 2011
Medicine & Science in Sports & Exercise, 2009
The purpose of this investigation was to determine the effects of 3 d of creatine supplementation... more The purpose of this investigation was to determine the effects of 3 d of creatine supplementation on thermoregulation and isokinetic muscular performance. 14 males performed two exercise bouts following 3 d of creatine supplementation and placebo. Subjects exercised for 60 min at 60--65% of VO2max in the heat followed by isokinetic muscular performance at 60, 180, and 300 o. s --1 . Dependent variables for pre-- and post--exercise included nude body weight, urine specific gravity, and serum creatinine levels. Total body water, extracellular water and intracellular water were measured pre--exercise. Core temperature was assessed every 5 min during exercise. Peak torque and fatigue index were used to assess isokinetic muscular performance. Core temperature increased during the run for both conditions. Total body water and extracellular water were significantly greater ( p &amp;amp;lt; .05) following creatine supplementation. No significant difference ( p &amp;amp;gt; .05) was found between conditions for intracellular water, nude body weight, urine specific gravity, and serum creatinine. Pre--exercise scores for urine specific gravity and serum creatinine were significantly less ( p &amp;amp;lt; .05) versus post--exercise. No significant differences ( p &amp;amp;gt; .05) were found in peak torque values or fatigue index between conditions for each velocity. A significant ( p &amp;amp;lt; .05) overall velocity effect was found for both flexion and extension. As velocity increased, mean peak torque values decreased. 3 d of creatine supplementation does not affect thermoregulation during submaximal exercise in the heat and is not enough to elicit an ergogenic effect for isokinetic muscle performance following endurance activity.
Medicine & Science in Sports & Exercise, 2009
Uploads
Papers by Tracey Matthews