Isokinetics and Exercise Science - Volume 25, issue 4

Authors: Ozdemir, Cigdem | Ozgünen, Kerem | Sarpel, Tunay | Günaştı, Ozgur | Bıldırcın, Caglar | Coşkun, Funda | Sadi Kurdak, S.

Article Type: Research Article

Abstract: BACKGROUND: Isokinetic dynamometers measure moment and calculate work and power values, which are generally used to interpret muscle performance. OBJECTIVE: This study aimed to determine the differences of peak moment (PM), work, and power between FRoM and calculated valid isokinetic sector (VIS) data to define the possibility of the misinterpretation of isokinetic dynamometer data. METHODS: Fourteen professional male soccer players who had ACL reconstruction were recruited to the muscle strengthening program which was conducted four days a week for six weeks with increasing training intensity each week. Isokinetic muscle peak moment, work, and …power of knee extensors and flexors were measured at angular velocities of 60, 120, 180 and 240 ∘ /s. RESULTS: The results of the standard full-RoM (FRoM) report were compared with the calculated VIS data. Analyses of the FRoM data showed that PM, work, and power values for both extensor and flexor muscle groups improved significantly. However, a comparison of FRoM and VIS data showed significant differences for the work and power values at 120, 180 and 240 ∘ /s. CONCLUSION: The evaluation of FRoM isokinetic data may cause improper interpretations in muscle performance, particularly for contractions with higher angular velocities. Show more

Keywords: ACL injury, valid isokinetic sector, muscle strength

DOI: 10.3233/IES-173137

Citation: Isokinetics and Exercise Science, vol. 25, no. 4, pp. 227-233, 2017

Authors: Aksoy, Duygu | Erman, Alparslan | Balcı, Nilüfer | Şentürk, Ümit Kemal

Article Type: Research Article

Abstract: OBJECTIVES: There is no consensus regarding the mechanism of strength enhancement of regular whole-body vibration training (WBVT), which involves only neural or neural plus muscular adaptation. This discord could be based on lack of protein supplement to diet in WBVT. This study aimed to clarify the effects of adding protein to the diet on hypertrophy and strength during whole-body vibration training (WBVT). METHODS: Young healty male adults, 20–30 years old were grouped into control (n = 15) and protein groups (n = 14). All experimental subjects …performed WBVT 3 days per week for 12 weeks. During WBVT, the protein group was provided with whey protein (1 g/kg) and the control group was provided with carbohydrate (1 g/kg starch isolate). Baseline measurements (pre-test) were done before the training program started while the last measurements (post-test) took place after the 12-w program. Body fat ratio and lean body mass were measured using bioelectrical impedance and hydrostatic weighing methods. Mid-thigh circumference (cm) and thigh skinfold measurement (cm) were used to calculate leg muscle area. The changes in muscle strength were evaluated by measuring jump height, hand-grip and leg strength. RESULTS: There were significant within-group differences between the post and in pre-training strength values of muscular strength but no between-group differences were noted. There were no changes in leg muscle area, body fat ratio and lean body mass in the control group. CONCLUSION: Protein supplementation does not affect strength and muscle mass after WBVT. Show more

Keywords: Isokinetic strength, strength training, athletic diet, lean body mass, hydrostatic weighing

DOI: 10.3233/IES-171131

Citation: Isokinetics and Exercise Science, vol. 25, no. 4, pp. 235-242, 2017

Authors: Karahan, Ali Yavuz | Bakdik, Suleyman | Ozen, Kemal Emre | Arslan, Serdar | Karpuz, Savas | Yilmaz, Nihal | Yildirim, Pelin | Oncu, Fatih | Cicekcibasi, Aynur

Article Type: Research Article

Abstract: BACKGROUND: The palmaris longus (PLM) is a fusiform-shaped muscle that appears in the superficial flexor compartment of the forearm. It has been suggested that PLM is a phylogenetically degenerate metacarpophalangeal joint flexor. OBJECTIVE: The aim of this study was to compare the strength of wrist flexion and extension in healthy volunteers with and without the PLM. METHODS: Sixty-four healthy subjects, 30 men and 34 women, 18–22 years old were enrolled in this study. The database consisted of 128 wrist tests. The inclusion criteria were as follows: sedentary lifestyle, unknown musculoskeletal disorders and right-handedness. …Musculoskeletal ultrasound imaging was used for assessing the presence of PLM. A hand-held digital dynamometer was used to assess the peak force of wrist extension and flexion. Data were analyzed separately for women and men RESULTS: The existence of right-sided PLM was 73.3% in male subjects and 55.9% in female subjects. For men, the strength of wrist flexion was 36.03 ± 13.92 N and 34.24 ± 12.23 N for the right and left side, respectively. For women, the respective strengths were 16.20 ± 7.29 N and 15.26 ± 6.79 N. For both sexes, there was no statistically significant difference between those with and without a PLM (p > 0.05). There was also no significant difference in the agonist/antagonist (flexion/extension) ratio of the wrist between those with and without a PLM in both sexes and sides. CONCLUSIONS: The existence or absence of PLM plays no role in the strength of either the flexors or extensors of the wrist. Show more

Keywords: Palmaris longus muscle, strength, wrist, ultrasound, dynamometer, agonist antagonist

DOI: 10.3233/IES-171139

Citation: Isokinetics and Exercise Science, vol. 25, no. 4, pp. 243-247, 2017

Authors: Seo, Kyoung Ho | Lee, Joong Hoon | Lee, Seung-Yeol | Chang, Chong-Bum | Lim, Jae-Young

Article Type: Research Article

Abstract: BACKGROUND: Relatively little is known about the longitudinal changes in strength and function in the early phase compared to long term outcome following reconstruction of the anterior cruciate ligament (ACL). OBJECTIVE: To assess the isokinetic concentric strength of the knee extensors and flexors as well as the distance jumped in the one-legged hop test in patients before and at 3, 6 and 12 months after (6 and 12 months for the hop test) reconstruction of the ACL. METHOD: Seventy-three men, aged 18–50 years took part in the study. The primary outcome measures were the International Knee …Documentation Committee (IKDC) scores at 3, 6, and 12 months after surgery and one-legged hop test at 6 and 12 months after post-reconstruction. RESULTS: There was a consistent increase in muscular strength between 3 and 12 months post-reconstruction. Fair but significant correlations were found between the IKDC score at 12 months and the peak moment of the knee extensors at 3 and 6 months (r = 0.450 and 0.429, respectively, p = 0.012). 60.2% of the participants satisfied the criteria of successful outcome based on IKDC scores and one-legged hop test at 12 months. The peak moment of knee extensor measured at 3 months after surgery was a significant predictive factor for successful outcome (p = 0.021). Patients in whom muscle strength had recovered well by 3 months after ACL reconstruction were more active in terms of sporting activities and exhibited better dynamic performance at the 1-year follow-up. CONCLUSION: Knee extension strengthening in early phase is crucial to restoring sporting performance after ACL reconstruction. Show more

Keywords: Isokinetic strength, ACL, IKDC score, one-legged hop test

DOI: 10.3233/IES-174128

Citation: Isokinetics and Exercise Science, vol. 25, no. 4, pp. 249-257, 2017

Authors: Bohannon, Richard W.

Article Type: Research Article

Abstract: OBJECTIVE: To describe and compare decreases in grip and knee extension strength accompanying aging. METHOD: Eighty-five community-dwelling women (20 to 79 years of age) participating in the validation phase of the NIH Toolbox for the Assessment of Neurological and Behavioral Function contributed data to this study. Their strength was measured bilaterally-grip with a hand dynamometer and isometric knee extension with an isokinetic dynamometer. Grip and knee extension strength measures of the left and right sides were combined and analyzed. RESULTS: Both combined grip strength and combined knee extension strength decreased with age. The …decreases were significant between the 60–79 year age group and the 20–39 year age group. Strength of the 60–79 year age group, described as a percentage of the 20–39 year age group, was significantly less for knee extension than for grip. CONCLUSION: Grip strength declines less than knee extension strength with age. Grip strength, therefore, may not fully capture the effect of age on muscle strength. Show more

Keywords: Hand, knee, muscle, strength, dynamometer

DOI: 10.3233/IES-171157

Citation: Isokinetics and Exercise Science, vol. 25, no. 4, pp. 259-261, 2017

Authors: Lafrance, Simon | Hsu, Jimmy | Caspin, Laura | Yee, Bennett | Robbins, Shawn | Preuss, Richard

Article Type: Research Article

Abstract: BACKGROUND: The ratio of hamstring to quadriceps strength (H/Q), from isokinetic testing, is often used to guide training or rehabilitation. OBJECTIVES: The primary objective was to develop an assessment protocol that produces reproducible H/Q data in a single testing session. METHODS: Twenty-four healthy subjects, 16 women and 8 men, were tested using a reliability study design (2 sessions, 5 repetitions). The main outcome measure was the dynamic control ratio at 60 ∘ /s (DCR60). Testing was also done at 120 ∘ /s, and concentrically at 180 ∘ …/s. Generalizability theory was used to determine the reliability (φ ) coefficient and the minimal detectable change MDC, and to extrapolate the data to develop an optimal assessment protocol, ideally using data from only one session. RESULTS: Single-session DCR60 data were reproducible (φ coefficient = 0.868, MDC95 = 0.144) using 5 repetitions, excluding the first repetition from the average. Values were improved by averaging over multiple sessions and repetitions, although little was gained from more than 2 sessions or 5 repetitions. Comparable results were found for testing at 120 ∘ /s. CONCLUSIONS: Reproducible DCR60 values may be derived from a single testing session of the hamstrings (in eccentric mode) and the quadriceps (in concentric mode). We recommend collecting five repetitions, and averaging the data for repetitions 2–5. Show more

Keywords: Knee, muscle strength, rehabilitation, reproducibility, dynamometer

DOI: 10.3233/IES-172150

Citation: Isokinetics and Exercise Science, vol. 25, no. 4, pp. 263-270, 2017

Authors: Smith, Cory M. | Housh, Terry J. | Hill, Ethan C. | Johnson, Glen O. | Schmidt, Richard J.

Article Type: Research Article

Abstract: BACKGROUND: Little is known regarding the influence of force application during fatigue when the total amount of work is equal. That is, do changes in force applications result in different fatigue mechanisms despite the overall work being the same. OBJECTIVE: The aim of the current study was to examine the effects of alternating forces versus repeated constant force muscle actions on the time course of changes in neuromuscular responses. METHODS: Sixteen adults performed 50-intermittent isometric leg extensions at alternating 40 then 80% maximal voluntary isometric contraction (40/80% MVIC) or repeated constant forces at 60% MVIC. Each …protocol resulted in equal, averaged force across all 50 repetitions. Electromyographic amplitude (EMG RMS), mechanomyographic (MMG) RMS, EMG mean power frequency (MPF), and MMG MPF were recorded from the vastus lateralis. RESULTS: Alternating force protocol resulted in less fatigue-induced changes in neuromuscular responses compared to repeated constant force protocol. The repeated constant force protocol resulted in earlier increases in EMG RMS and MMG RMS as well as earlier decreases in EMG MPF and MMG MPF compared to the alternating force protocol. CONCLUSIONS: Fatigue in occupational, sporting activities, or various fatiguing tasks may be dependent on the order that force is applied. Show more

Keywords: Physical work, loading, work measurement, work physiology, musculoskeletal system

DOI: 10.3233/IES-172168

Citation: Isokinetics and Exercise Science, vol. 25, no. 4, pp. 271-279, 2017

Authors: Dobbs, Ian J. | Watkins, Casey M. | Barillas, Saldiam R. | Wong, Megan A. | Brown, Lee E.

Article Type: Research Article

Abstract: BACKGROUND: Assessing players’ leg strength ratios prior to season is important in order to measure performance and identify weaknesses. Leg ratios are calculated by dividing the moment of hamstring by quadriceps. The simple (concentric only) HQ ratio and the dynamic control ratio (DCR) (Hamstring eccentric/Quadriceps concentric) are used to detect asymmetry, knee strength, and bilateral deficit (BD). However, open (OKC) and closed kinetic chain (CKC) tests potentially provide different information regarding muscle strength and balance. OBJECTIVE: The purpose of this study was to measure the abovementioned ratios in male and female amateur rugby union players and …to assess difference between OKC and CKC tests. METHODS: Six males (age = 22.00 ± 2.61 y, height = 172.67 ± 6.12 cm, mass = 80.28 ± 11.13 kg) and 11 females (age = 24.73 ± 3.66, height = 164.00 ± 5.23, mass = 74.00 ± 18.14 kg) rugby union players performed an isometric-mid thigh pull (IMTP) and isokinetic knee extension/flexion at 60 ∘ /s. RESULTS: The non-dominant leg simple ratio (0.81 ± 0.13%) was greater than dominant (0.74 ± 0.14%) while the DCR (0.81 ± 0.14%) was greater than simple ratio (0.73 ± 0.10%). The OKC BD (- 21.00 ± 13.86%) was significantly greater than its CKC counterpart (- 6.76 ± 9.79%) while males’ OKC BD (- 30.55 ± 14.93%) was significantly greater than females’ (- 15.79 ± 10.55%). CONCLUSION: The DCR may be more sport specific when measuring knee strength, while an OKC test is more likely to detect BD due to muscle isolation. Show more

Keywords: Muscle, quadriceps, hamstring, isokinetic dynamometer, isometric mid-thigh pull

DOI: 10.3233/IES-171171

Citation: Isokinetics and Exercise Science, vol. 25, no. 4, pp. 281-287, 2017

Authors: Lazarou, Lazaros | Kofotolis, Nikolaos | Malliou, Paraskevi | Kellis, Eleftherios

Article Type: Research Article

Abstract: BACKGROUND: After ankle sprains, therapists may use proprioceptive training programs to manage residual symptoms and reduce the risk for recurrent injuries. However, evidence on program effectiveness is limited. OBJECTIVE: To investigate effectiveness of balance and proprioceptive neuromuscular facilitation (PNF) programs in individuals with sprain. METHODS: Participants were recruited from a rehabilitation center and were randomly allocated to a balance or PNF group. Both groups received 10 training sessions, within a six-week period. Ankle position sense, isokinetic strength and EMG activity were assessed by a blinded investigator at baseline, at the end of training …and eight weeks after training. Recurrent injuries were recorded 12 months after training. RESULTS: Twenty participants provided follow-up data. Eight weeks after training, significant (p < 0.017) gains were found in most strength measures for both groups, apart from dorsiflexion strength (p > 0.05). For the balance group, there were no recurrent injuries and for the PNF group the recurrent injury rate was 20%. Eight weeks after training, the balance group significantly (p < 0.017) improved plantar flexion position sense and EMG activity of peroneus longus muscle and the PNF group significantly (p < 0.017) improved EMG activity of tibialis anterior muscle. CONCLUSIONS: For individuals with sprain, balance and PNF programs are recommended for ankle strengthening. They may also be effective in reducing the risk for recurrent injuries. Show more

Keywords: Ankle sprain, balance training, PNF training, joint position sense, isokinetic strength, electromyography, recurrent injury

DOI: 10.3233/IES-171146

Citation: Isokinetics and Exercise Science, vol. 25, no. 4, pp. 289-300, 2017

Authors: Lee, Kyeongbong | Kim, Minkyu | Ha, Hyungeun | Lee, Wanhee

Article Type: Research Article

Abstract: BACKGROUND: Lateral abdominal muscle strengthening exercise can improve the function and motor control of core musculature, but the influence of exercise posture and unstable support surface is controversial. OBJECTIVE: To evaluate the influence of bridge exercise type and support surface on abdominal muscle thickness during three bridge exercises with two different support surfaces. METHODS: Real-time ultrasonography was used to measure the muscle thickness of the transverse abdominis, internal oblique, and external oblique muscles in 45 healthy volunteers. The supine, prone, and flank bridge exercise were performed on stable and unstable support surfaces. …RESULTS: The thickness of all muscles was significantly increased during flank compared to supine bridge exercise and prone with stable support (p < 0.05) but not in prone vs. supine. Muscle thickness was significantly increased in prone compared to supine bridge and flank compared to supine and prone (p < 0.05) with unstable support. However, only internal oblique muscle thickness was significantly increased in unstable support surface compared to stable during prone bridge exercise. CONCLUSION: Bridge exercises performed with unstable support do not influence the contraction thickness of lateral abdominal muscles any more than those performed with stable support. In healthy individuals, thickening of abdominal muscles is influenced more by maintaining a specific posture than by the support surface when the target muscles are engaged as agonists. Show more

Keywords: Lateral abdominal muscle, contraction thickness, bridge exercise, unstable support surface, rehabilitative ultrasound image

DOI: 10.3233/IES-171172

Citation: Isokinetics and Exercise Science, vol. 25, no. 4, pp. 301-308, 2017

Authors: Park, Sun-Ju | Shim, Su-Jin | Choi, Bo-Ram

Article Type: Research Article

Abstract: BACKGROUND: When various balance exercises are combined with strengthening or stretching exercises, the specific effects of any individual balance exercise are unclear. OBJECTIVE: The purpose of this study was to compare muscle activation and ratio in the quadriceps, hamstring, and gastrocnemius muscles in balance exercises. METHODS: In total, 20 healthy volunteers participated. The balance exercises consisted of standing on one-leg stand, a lunge, and trunk rotation. Electromyography data were collected from lateral quadriceps (LQ), lateral hamstring (LH), lateral gastrocnemius (LG), medial quadriceps (MQ), medial hamstring (MH), and medial gastrocnemius (MG). One-way repeated-measures analysis …of variance was used to assess the statistical significance of the muscle activation, muscle co-activation, and the muscle activation/co-activation ratio in the balance exercises. RESULTS: Compared with the other exercises, co-activation of the MQMH, LQLH, and LHLG increased significantly during the lunge (P < 0.05). During the lunge, the increase in LQLH and LHLG co-activation was significantly greater than that in MQMH and MHMG co-activation (P < 0.05). CONCLUSIONS: Co-activation of lateral muscles was greater than in the medial muscles during lunge exercises with repeated lunge exercise potentially causing lateral knee joint compression. Therefore, physical therapists and/or athletic trainers should pay specific attention to use of lunge exercise within the framework of balance exercise program. Show more

Keywords: Balance exercise, lunge, one-leg stand, muscle co-activation

DOI: 10.3233/IES-173154

Citation: Isokinetics and Exercise Science, vol. 25, no. 4, pp. 309-316, 2017