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597 KiB

Open AccessArticle

Lateral Squats Significantly Decrease Sprint Time in Collegiate Baseball Athletes

by Jason B. White, Trevor P. Dorian and Margaret T. Jones

Sports 2016, 4(1), 19; https://doi.org/10.3390/sports4010019 - 7 Mar 2016

Cited by 1 | Viewed by 8823

Abstract

The purpose was to examine the effect of prior performance of dumbbell lateral squats (DBLS) on an agility movement-into-a-sprint (AMS) test. Twelve collegiate, resistance-trained, baseball athletes participated in three sessions separated by three days. Session One consisted of AMS baseline test, DBLS 5-RM [...] Read more.

The purpose was to examine the effect of prior performance of dumbbell lateral squats (DBLS) on an agility movement-into-a-sprint (AMS) test. Twelve collegiate, resistance-trained, baseball athletes participated in three sessions separated by three days. Session One consisted of AMS baseline test, DBLS 5-RM test, and experimental protocol familiarization. Subjects were randomly assigned the protocol order for Sessions Two and Three, which consisted of warm up followed by 1-min sitting (no-DBLS) or performing the DBLS for 1 × 5 repetitions @ 5RM for each leg. Four minutes of slow recovery walking preceded the AMS test, which consisted of leading off a base and waiting for a visual stimulus. In reaction to stimulus, subjects exerted maximal effort while moving to the right by either pivoting or drop stepping and sprinting for 10 yards (yd). In Session Three, subjects switched protocols (DBLS, no-DBLS). Foot contact time (FCT), stride frequency (SF), stride length (SL), and 10-yd sprint time were measured. There were no differences between conditions for FCT, SF, or SL. Differences existed between DBLS (1.85 ± 0.09 s) and no-DBLS (1.89 ± 0.10 s) for AMS (p = 0.03). Results from the current study support the use of DBLS for performance enhancement prior to performing the AMS test. Full article

(This article belongs to the Special Issue Strength and Conditioning)

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180 KiB

Open AccessArticle

Relationship of Two Vertical Jumping Tests to Sprint and Change of Direction Speed among Male and Female Collegiate Soccer Players

by Isaiah T. McFarland, J. Jay Dawes, Craig L. Elder and Robert G. Lockie

Sports 2016, 4(1), 11; https://doi.org/10.3390/sports4010011 - 16 Feb 2016

Cited by 98 | Viewed by 15857

Abstract

In collegiate level soccer acceleration, maximal velocity and agility are essential for successful performance. Power production is believed to provide a foundation for these speed qualities. The purpose of this study was to determine the relationship of change of direction speed, acceleration, and [...] Read more.

In collegiate level soccer acceleration, maximal velocity and agility are essential for successful performance. Power production is believed to provide a foundation for these speed qualities. The purpose of this study was to determine the relationship of change of direction speed, acceleration, and maximal velocity to both the counter movement jump (CMJ) and squat jump (SJ) in collegiate soccer players. Thirty-six NCAA Division II soccer players (20 males and 16 females) were tested for speed over 10 and 30 m, CODS (T-test, pro agility) and power (CMJ, SJ). Independent t-tests (p ≤ 0.05) were used to derive gender differences, and Pearson’s correlations (p ≤ 0.05) calculated relationships between the different power and speed tests. Female subjects displayed moderate-to-strong correlations between 30 m, pro agility and T-test with the CMJ (r = −0.502 to −0.751), and SJ (r = −0.502 to −0.681). Moderate correlations between 10 and 30 m with CMJ (r = −0.476 and −0.570) and SJ (r = −0.443 and −0.553, respectively) were observed for males. Moderate to strong relationships exist between speed and power attributes in both male and female collegiate soccer players, especially between CMJ and maximal velocity. Improving stretch shortening cycle (SSC) utilization may contribute to enhanced sport-specific speed. Full article

(This article belongs to the Special Issue Strength and Conditioning)

576 KiB

Open AccessArticle

Effects of Short-Term Dynamic Constant External Resistance Training and Subsequent Detraining on Strength of the Trained and Untrained Limbs: A Randomized Trial

by Pablo B. Costa, Trent J. Herda, Ashley A. Herda and Joel T. Cramer

Sports 2016, 4(1), 7; https://doi.org/10.3390/sports4010007 - 27 Jan 2016

Cited by 2 | Viewed by 6327

Abstract

Short-term resistance training has been shown to increase isokinetic muscle strength and performance after only two to nine days of training. The purpose of this study was to examine the effects of three days of unilateral dynamic constant external resistance (DCER) training and [...] Read more.

Short-term resistance training has been shown to increase isokinetic muscle strength and performance after only two to nine days of training. The purpose of this study was to examine the effects of three days of unilateral dynamic constant external resistance (DCER) training and detraining on the strength of the trained and untrained legs. Nineteen men were randomly assigned to a DCER training group or a non-training control group. Subjects visited the laboratory eight times, the first visit was a familiarization session, the second visit was a pre-training assessment, the subsequent three visits were for training sessions (if assigned to the training group), and the last three visits were post-training assessments 1, 2, and 3 (i.e., 48 h, 1 week, and 2 weeks after the final training session). Strength increased in both trained and untrained limbs from pre- to post-training assessment 1 for the training group and remained elevated at post-training assessments 2 and 3 (p ≤ 0.05). No changes were observed in the control (p > 0.05). Possible strength gains from short-term resistance training have important implications in clinical rehabilitation settings, sports injury prevention, as well as other allied health fields such as physical therapy, occupational therapy, and athletic training. Full article

(This article belongs to the Special Issue Strength and Conditioning)

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544 KiB

Open AccessArticle

Effects of Respiratory Muscle Warm-up on High-Intensity Exercise Performance

by Taylor S. Thurston, Jared W. Coburn, Lee E. Brown, Albert Bartolini, Tori L. Beaudette, Patrick Karg, Kathryn A. McLeland, Jose A. Arevalo, Daniel A. Judelson and Andrew J. Galpin

Sports 2015, 3(4), 312-324; https://doi.org/10.3390/sports3040312 - 5 Nov 2015

Cited by 2 | Viewed by 7226

Abstract

Exercise performance is partially limited by the functionality of the respiratory musculature. Training these muscles improves steady-state exercise performance. However, less is known about the efficacy of executing a respiratory muscle warm-up (RWU) immediately prior to high-intensity exercise. Our study purpose was to [...] Read more.

Exercise performance is partially limited by the functionality of the respiratory musculature. Training these muscles improves steady-state exercise performance. However, less is known about the efficacy of executing a respiratory muscle warm-up (RWU) immediately prior to high-intensity exercise. Our study purpose was to use a practitioner-friendly airflow restriction device to investigate the effects of a high, medium, or low intensity RWU on short, high-intensity exercise and pulmonary, cardiovascular, and metabolic function. Eleven recreationally active, males (24.9 ± 4.2 y, 178.8 ± 9.0 cm, 78.5 ± 10.4 kg, 13.4% ± 4.2% body fat) cycled at 85% peak power to exhaustion (TTE) following four different RWU conditions (separate days, in random order): (1) high; (2) medium; (3) low airflow inspiration restriction, or no RWU. When analyzed as a group, TTE did not improve following any RWU (4.73 ± 0.33 min). However, 10 of the 11 participants improved ≥25 s in one of the three RWU conditions (average = 47.6 ± 13.2 s), which was significantly better than (p < 0.05) the control trial (CON). Neither blood lactate nor perceived difficulty was altered by condition. In general, respiratory exchange ratios were significantly lower during the early stages of TTE in all RWU conditions. Our findings suggest RWU efficacy is predicated on identifying optimal inspiration intensity, which clearly differs between individuals. Full article

(This article belongs to the Special Issue Strength and Conditioning)

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825 KiB

Open AccessArticle

Outcomes following Hip and Quadriceps Strengthening Exercises for Patellofemoral Syndrome: A Systematic Review and Meta-Analysis

by Adebisi Bisi-Balogun and Firdevs Torlak

Sports 2015, 3(4), 281-301; https://doi.org/10.3390/sports3040281 - 23 Oct 2015

Cited by 2 | Viewed by 8436

Abstract

There is growing evidence to support change in the rehabilitation strategy of patellofemoral pain syndrome (PFPS) from traditional quadriceps strengthening exercises to inclusion of hip musculature strengthening in individuals with PFPS. Several studies have evaluated effects of quadriceps and hip musculature strengthening on [...] Read more.

There is growing evidence to support change in the rehabilitation strategy of patellofemoral pain syndrome (PFPS) from traditional quadriceps strengthening exercises to inclusion of hip musculature strengthening in individuals with PFPS. Several studies have evaluated effects of quadriceps and hip musculature strengthening on PFPS with varying outcomes on pain and function. This systematic review and meta-analysis aims to synthesize outcomes of pain and function post-intervention and at follow-up to determine whether outcomes vary depending on the exercise strategy in both the short and long term. Electronic databases including MEDLINE, EMBASE, CINAHL, Web of Science, PubMed, Pedro database, Proquest, Science direct, and EBscoHost databases were searched for randomized control trials published between 1st of January 2005 and 31st of June 2015, comparing the outcomes of pain and function following quadriceps strengthening and hip musculature strengthening exercises in patients with PFPS. Two independent reviewers assessed each paper for inclusion and quality. Means and SDs were extracted from each included study to allow effect size calculations and comparison of results. Six randomized control trials met the inclusion criteria. Limited to moderate evidence indicates that hip abductor strengthening was associated with significantly lower pain post-intervention (SMD −0.88, −1.28 to −0.47 95% CI), and at 12 months (SMD −3.10, −3.71 to −2.50 95% CI) with large effect sizes (greater than 0.80) compared to quadriceps strengthening. Our findings suggest that incorporating hip musculature strengthening in management of PFPS tailored to individual ability will improve short-term and long-term outcomes of rehabilitation. Further research evaluating the effects of quadriceps and hip abductors strengthening focusing on reduction in anterior knee pain and improvement in function in management of PFPS is needed. Full article

(This article belongs to the Special Issue Strength and Conditioning)

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328 KiB

Open AccessArticle

Individual Responses for Muscle Activation, Repetitions, and Volume during Three Sets to Failure of High- (80% 1RM) versus Low-Load (30% 1RM) Forearm Flexion Resistance Exercise

by Nathaniel D. M. Jenkins, Terry J. Housh, Samuel L. Buckner, Haley C. Bergstrom, Kristen C. Cochrane, Cory M. Smith, Ethan C. Hill, Richard J. Schmidt and Joel T. Cramer

Sports 2015, 3(4), 269-280; https://doi.org/10.3390/sports3040269 - 25 Sep 2015

Cited by 6 | Viewed by 8461

Abstract

This study compared electromyographic (EMG) amplitude, the number of repetitions completed, and exercise volume during three sets to failure of high- (80% 1RM) versus low-load (30% 1RM) forearm flexion resistance exercise on a subject-by-subject basis. Fifteen men were familiarized, completed forearm flexion 1RM [...] Read more.

This study compared electromyographic (EMG) amplitude, the number of repetitions completed, and exercise volume during three sets to failure of high- (80% 1RM) versus low-load (30% 1RM) forearm flexion resistance exercise on a subject-by-subject basis. Fifteen men were familiarized, completed forearm flexion 1RM testing. Forty-eight to 72 h later, the subjects completed three sets to failure of dumbbell forearm flexion resistance exercise with 80% (n = 8) or 30% (n = 7) 1RM. EMG amplitude was calculated for every repetition, and the number of repetitions performed and exercise volume were recorded. During sets 1, 2, and 3, one of eight subjects in the 80% 1RM group demonstrated a significant linear relationship for EMG amplitude versus repetition. For the 30% 1RM group, seven, five, and four of seven subjects demonstrated significant linear relationships during sets 1, 2, and 3, respectively. The mean EMG amplitude responses show that the fatigue-induced increases in EMG amplitude for the 30% 1RM group and no change in EMG amplitude for the 80% 1RM group resulted in similar levels of muscle activation in both groups. The numbers of repetitions completed were comparatively greater, while exercise volumes were similar in the 30% versus 80% 1RM group. Our results, in conjunction with those of previous studies in the leg extensors, suggest that there may be muscle specific differences in the responses to high- versus low-load exercise. Full article

(This article belongs to the Special Issue Strength and Conditioning)

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180 KiB

Open AccessArticle

Effectiveness of Different Rest Intervals Following Whole-Body Vibration on Vertical Jump Performance between College Athletes and Recreationally Trained Females

by Nicole C. Dabbs, Jon A. Lundahl and John C. Garner

Sports 2015, 3(3), 258-268; https://doi.org/10.3390/sports3030258 - 18 Sep 2015

Cited by 5 | Viewed by 5084

Abstract

The purpose of this study was to evaluate the effect of different rest intervals following whole-body vibration on counter-movement vertical jump performance. Sixteen females, eight recreationally trained and eight varsity athletes volunteered to participate in four testing visits separated by 24 h. Visit [...] Read more.

The purpose of this study was to evaluate the effect of different rest intervals following whole-body vibration on counter-movement vertical jump performance. Sixteen females, eight recreationally trained and eight varsity athletes volunteered to participate in four testing visits separated by 24 h. Visit one acted as a familiarization visit where subjects were introduced to the counter-movement vertical jump and whole-body vibration protocols. Visits 2–4 contained 2 randomized conditions. Whole-body vibration was administered in four bouts of 30 s with 30 s rest between bouts. During whole-body vibration subjects performed a quarter squat every 5 s, simulating a counter-movement vertical jump. Whole-body vibration was followed by three counter-movement vertical jumps with five different rest intervals between the vibration exposure and jumping. For a control condition, subjects performed squats with no whole-body vibration. There was a significant (p < 0.05) main effect for time for vertical jump height, peak power output, and relative ground reaction forces, where a majority of individuals max jump from all whole-body vibration conditions was greater than the control condition. There were significant (p < 0.05) group differences, showing that varsity athletes had a greater vertical jump height and peak power output compared to recreationally trained females. There were no significant (p > 0.05) group differences for relative ground reaction forces. Practitioners and/or strength and conditioning coaches may utilize whole-body vibration to enhance acute counter-movement vertical jump performance after identifying individuals optimal rest time in order to maximize the potentiating effects. Full article

(This article belongs to the Special Issue Strength and Conditioning)

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125 KiB

Open AccessArticle

Angle Specific Analysis of Side-to-Side Asymmetry in the Shoulder Rotators

by Cassio V. Ruas, Ronei S. Pinto, Eduardo L. Cadore and Lee E. Brown

Sports 2015, 3(3), 236-245; https://doi.org/10.3390/sports3030236 - 31 Aug 2015

Cited by 6 | Viewed by 4852

Abstract

Although side-to-side asymmetry of the shoulder rotators calculated by independent peak torque (IPT) has been used for interpretation of injury risks in athletes, it may not measure strength through the entire range of motion (ROM) tested. The aim of this study was to [...] Read more.

Although side-to-side asymmetry of the shoulder rotators calculated by independent peak torque (IPT) has been used for interpretation of injury risks in athletes, it may not measure strength through the entire range of motion (ROM) tested. The aim of this study was to compare side-to-side asymmetry of the shoulder rotators between independent peak torque (IPT) and ten-degree angle specific torque (AST). Twenty healthy adult males (24.65 ± 2.4 years) performed concentric and eccentric internal rotation (IR) and external rotation (ER) of the preferred and non-preferred arms on an isokinetic dynamometer at 60°/s through 150° of total ROM. The total ROM was divided into 14 ten-degree angles of the physiological ROM from −90° of ER to 60° of IR. Concentric and eccentric IR IPT (10.5% ± 8.7% and 12.1% ± 7.2%) and ER IPT (13.6% ± 9.8% and 8.7% ± 5.6%) were significantly less than AST at several angles (p < 0.05). IPT might lead to erroneous interpretations of side-to-side asymmetry in the shoulder rotators and does not represent the entire ROM tested. This information could be used to prescribe strength exercises to enhance overhead performance and reduce risk of shoulder injuries. Full article

(This article belongs to the Special Issue Strength and Conditioning)

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118 KiB

Open AccessCommunication

The Effect of Kettlebell Swing Load and Cadence on Physiological, Perceptual and Mechanical Variables

by Michael J. Duncan, Rosanna Gibbard, Leanne M. Raymond and Peter Mundy

Sports 2015, 3(3), 202-208; https://doi.org/10.3390/sports3030202 - 7 Aug 2015

Cited by 6 | Viewed by 7805

Abstract

This study compared the physiological, perceptual and mechanical responses to kettlebell swings at different loads and swing speeds. Following familiarization 16 strength trained participants (10 males, six females, mean age ± SD = 23 ± 2.9) performed four trials: 2 min kettlebell swings [...] Read more.

This study compared the physiological, perceptual and mechanical responses to kettlebell swings at different loads and swing speeds. Following familiarization 16 strength trained participants (10 males, six females, mean age ± SD = 23 ± 2.9) performed four trials: 2 min kettlebell swings with an 8 kg kettlebell at a fast cadence; 2 min kettlebell swings with an 8 kg kettlebell at a slow cadence; 4 min kettlebell swings with a 4 kg kettlebell at a fast cadence; 4 min kettlebell swings with a 4 kg kettlebell at a slow cadence. Repeated measured analysis of variance indicated no significant differences in peak blood lactate or peak net vertical force across loads and cadences (P > 0.05). Significant main effect for time for heart rate indicated that heart rate was higher at the end of each bout than at mid-point (P = 0.001). A significant Load X cadence interaction for rating of perceived exertion (RPE) (P = 0.030) revealed that RPE values were significantly higher in the 8 kg slow cadence condition compared to the 4 kg slow (P = 0.002) and 4 kg fast (P = 0.016) conditions. In summary, this study indicates that the physiological and mechanical responses to kettlebell swings at 4 kg and 8 kg loads and at fast and slow cadence were similar, whereas the perceptual response is greater when swinging an 8 kg kettlebell at slow cadence. Full article

(This article belongs to the Special Issue Strength and Conditioning)

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116 KiB

Open AccessArticle

A Comparison of Upper Body Strength between Rock Climbing and Resistance Trained Men

by Kristina M. Macias, Lee E. Brown, Jared W. Coburn and David D. Chen

Sports 2015, 3(3), 178-187; https://doi.org/10.3390/sports3030178 - 30 Jul 2015

Cited by 8 | Viewed by 9416

Abstract

Studies have shown that advanced rock climbers have greater upper body strength than that of novice climbers or non-climbers. The purpose of this study was to compare upper body strength between rock climbing and resistance trained men. Fifteen resistance trained men (age 25.28 [...] Read more.

Studies have shown that advanced rock climbers have greater upper body strength than that of novice climbers or non-climbers. The purpose of this study was to compare upper body strength between rock climbing and resistance trained men. Fifteen resistance trained men (age 25.28 ± 2.26 yrs; height 177.45 ± 4.08 cm; mass 85.17 ± 10.23 kg; body fat 10.13 ± 5.40%) and 15 rock climbing men (age 23.25 ± 2.23 yrs; height 175.57 ± 8.03 cm; mass 66.66 ± 9.40 kg; body fat 6.86 ± 3.82%) volunteered to participate. Rock climbing (RC) men had been climbing for at least two years, 2–3 times a week, able to climb at least a boulder rating of V4–5 and had no current injuries. Resistance trained (RT) men had been total body strength training for at least two years, 2–3 times a week with no current injuries. Each participant performed pull-ups to failure, grip strength, and pinch strength. RT were significantly older and heavier than RC. RC performed significantly more pull-ups (19.31 ± 4.31) than RT (15.64 ± 4.82). RC had greater relative pinch strength (R 0.27 ± 0.10 kg/kg; L 0.24 ± 0.07 kg/kg) than RT (R 0.19 ± 0.04 kg/kg; L 0.16 ± 0.05 kg/kg) and greater relative grip strength (R 0.70 ± 0.10 kg/kg; L 0.65 ± 0.12 kg/kg) than RT (R 0.57 ± 0.14 kg/kg; L 0.56 ± 0.15 kg/kg). Overall, RC men demonstrated greater performance in tests involving relative strength when compared to RT men. Rock climbing can promote increased upper body strength even in the absence of traditional resistance training. Full article

(This article belongs to the Special Issue Strength and Conditioning)

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Review

Jump to: Research

262 KiB

Open AccessReview

Less Is More: The Physiological Basis for Tapering in Endurance, Strength, and Power Athletes

by Kevin A. Murach and James R. Bagley

Sports 2015, 3(3), 209-218; https://doi.org/10.3390/sports3030209 - 21 Aug 2015

Cited by 18 | Viewed by 20465

Abstract

Taper, or reduced-volume training, improves competition performance across a broad spectrum of exercise modes and populations. This article aims to highlight the physiological mechanisms, namely in skeletal muscle, by which taper improves performance and provide a practical literature-based rationale for implementing taper in [...] Read more.

Taper, or reduced-volume training, improves competition performance across a broad spectrum of exercise modes and populations. This article aims to highlight the physiological mechanisms, namely in skeletal muscle, by which taper improves performance and provide a practical literature-based rationale for implementing taper in varied athletic disciplines. Special attention will be paid to strength- and power-oriented athletes as taper is under-studied and often overlooked in these populations. Tapering can best be summarized by the adage “less is more” because maintained intensity and reduced volume prior to competition yields significant performance benefits. Full article

(This article belongs to the Special Issue Strength and Conditioning)

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