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Feasibility of Velocity Loss-Based Volume Prescription During Constant-Load and Chain-Based Smith Machine Back Squats

2026年7月18日 更新者：Zongwei Chen、South China Normal University
The goal of this observational study was to evaluate the feasibility of percentage of velocity loss (%VL)-based approaches for prescribing training volume during constant-load and chain-based Smith machine back squats. The study aimed to answer whether %VL can be expressed as the maximum number of repetitions (%Rep) in constant-load and chain-based Smith machine squats. Twenty-six resistance-trained men performed repetitions-to-failure tests under variable (VRT) and constant resistance training (CRT). The %Rep attained before reaching different levels of effort were compared between VRT and CRT across various loads and sessions. Furthermore, this study evaluated the influence of different factors on the predictive accuracy of the %Rep-%VL relationships. These findings will provide evidence-based evidence in prescribing and monitoring intra-set volume.

研究概览

地位

完全的

条件

干预/治疗

详细说明

The goal of this observational study was to evaluate the feasibility of percentage of velocity loss (%VL)-based approaches for prescribing training volume during constant-load and chain-based Smith machine back squats. The study aimed to answer whether %VL can be expressed as the maximum number of repetitions (%Rep) in constant-load and chain-based Smith machine squats. Twenty-six resistance-trained men performed repetitions-to-failure tests at 85%, 75%, and 65% of their constant-load one-repetition maximum (1RM) under variable (VRT; 40% of the total external load provided by chains) and constant resistance training (CRT; 0% chains). The %Rep attained before reaching low (10% VL), moderate (20% VL), and high (30% VL) levels of effort were compared between VRT and CRT across various loads and sessions. Furthermore, this study evaluated the influence of regression type (individual vs. general), load specificity (load-specific vs. multiple-load), and loading configuration (CRT vs. VRT) on the predictive accuracy of the %Rep-%VL relationships established in session 1 for estimating %Rep in session 2. These findings will provide evidence-based evidence in prescribing and monitoring intra-set volume.

研究类型

观察性的

注册 (实际的)

26

联系人和位置

本节提供了进行研究的人员的详细联系信息，以及有关进行该研究的地点的信息。

学习地点

  • 中国
    • Guangdong
      • Guangzhou、Guangdong、中国、510006
        • School of Physical Education and Sports Science, South China Normal University

参与标准

研究人员寻找符合特定描述的人，称为资格标准。这些标准的一些例子是一个人的一般健康状况或先前的治疗。

资格标准

适合学习的年龄

  • 成人
  • 年长者

接受健康志愿者

是的

取样方法

非概率样本

研究人群

Participant characteristics (mean ± standard deviation [range]) included: age, 20.4 ± 2.1 (18-25) years; body height, 1.78 ± 0.05 (1.68-1.87) m; body mass, 71.7 ± 7.5 (60.0-91.4) kg; training experience, 3.5 ± 1.8 (1-10) years; and constant-load 1RM, 135.4 ± 17.4 (95-163) kg, corresponding to 1.89 ± 0.21 (1.58-2.28) times body mass.

描述

Inclusion Criteria:

  • at least 1 year of resistance training experience, performing back squats at least once per week.
  • proficiency in the Smith machine back squat executed at maximal intended velocity.
  • a constant-load 1RM of ≥ 1.5 times their body mass.
  • no reported musculoskeletal injuries in the past three months.

Exclusion Criteria:

  • Voluntary withdrawal or injury.
  • Not satisfied with inclusion label.

学习计划

本节提供研究计划的详细信息，包括研究的设计方式和研究的衡量标准。

研究是如何设计的？

设计细节

研究衡量的是什么？

主要结果指标

结果测量
措施说明
大体时间
The %Rep attained before reaching the 10%, 20%, and 30% VL thresholds
大体时间：April 1st, 2026
The %Rep attained before reaching the 10%, 20%, and 30% VL thresholds was recorded across all loads, sessions, and loading configurations.
April 1st, 2026
The %rep predictive accuracy
大体时间：April 1st, 2026
To assess predictive accuracy, second-order polynomial regression equations were generated from the first session of each loading configuration using all repetitions within a set, setting %Rep as the dependent variable and %VL as the independent variable. These equations were constructed using different regression types (individual vs. general), load specificities (load-specific vs. multiple-load), and loading configurations (CRT vs. VRT). During the second session, the actual %VL recorded after reaching the 10%, 20%, and 30% VL thresholds was substituted into the corresponding first-session equations to derive the predicted %Rep. Then, the absolute estimation error was calculated as (|actual %Rep - predicted %Rep|). In cases where muscular failure occurred before a specific %VL threshold was reached (e.g., 30% VL), the %VL of the final completed repetition was recorded, and the corresponding actual %Rep was defined as 100%.
April 1st, 2026

合作者和调查者

在这里您可以找到参与这项研究的人员和组织。

赞助

South China Normal University

出版物和有用的链接

负责输入研究信息的人员自愿提供这些出版物。这些可能与研究有关。

有用的网址

研究记录日期

这些日期跟踪向 ClinicalTrials.gov 提交研究记录和摘要结果的进度。研究记录和报告的结果由国家医学图书馆 (NLM) 审查，以确保它们在发布到公共网站之前符合特定的质量控制标准。

研究主要日期

学习开始 (实际的)

2025年10月7日

初级完成 (实际的)

2026年1月10日

研究完成 (实际的)

2026年5月1日

研究注册日期

首次提交

2026年7月15日

首先提交符合 QC 标准的

2026年7月18日

首次发布 (实际的)

2026年7月22日

研究记录更新

最后更新发布 (实际的)

2026年7月22日

上次提交的符合 QC 标准的更新

2026年7月18日

最后验证

2026年7月1日

更多信息

与本研究相关的术语

关键字

其他研究编号

  • SCNU-SPT-2025-055

计划个人参与者数据 (IPD)

计划共享个人参与者数据 (IPD)？

是的

IPD 计划说明

The data that support the findings of this study are available from the corresponding author upon reasonable request.

IPD 共享时间框架

Individual participant data and supporting documents will become available after publication of the study results and will remain available for 5 years.

IPD 共享访问标准

Individual participant data (IPD) will be shared in anonymized form with qualified researchers for scientific purposes. The shared data will include lifting velocity of each repetition completed.

IPD 共享支持信息类型

  • 研究方案
  • 树液
  • 企业社会责任

药物和器械信息、研究文件

研究美国 FDA 监管的药品

不

研究美国 FDA 监管的设备产品

不

此信息直接从 clinicaltrials.gov 网站检索，没有任何更改。如果您有任何更改、删除或更新研究详细信息的请求，请联系 register@clinicaltrials.gov. clinicaltrials.gov 上实施更改，我们的网站上也会自动更新.

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