6.5 Forearm Plank, Y Balance Test & Predicted 1-RM Protocols

6.5 Forearm Plank, Y Balance Test & Predicted 1-RM Protocols

CSEP's Tour of the Second Edition (2019) lists two new musculoskeletal protocols, the Forearm Plank and the Y Balance Test. It also notes that the Predicted One Repetition Maximum (1-RM) protocol moved into Step 2 – Assess with the other musculoskeletal protocols. The Third Edition (2021) Toolkit includes a Predicting 1-RM Data Collection Worksheet (Tool #23) and a Y Balance Test Data Collection Worksheet (Tool #24). These protocols serve CSEP-CPT competencies 3.21 and 3.22 (evaluating strength, endurance, power and balance, and their strengths and weaknesses) and 4.17 and 4.18 (predicting 1-RM, and predicted versus actual 1-RM).

CSEP's physician guidance letter for the CSEP-PATH assessment lists six musculoskeletal tests: grip strength, push-up, sit and reach, vertical jump, back extension and one leg stance. The Second Edition added three more. The full menu is therefore:

• grip strength;
• push-ups;
• predicted 1-RM;
• sit and reach;
• vertical jump;
• back extension;
• forearm plank;
• Y Balance Test;
• one leg stance, or another appropriate musculoskeletal test.

As with every protocol, choose tests that match the client's goals and abilities. A client can decline any test.

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Forearm Plank (Anterior Core Endurance)

What it measures: isometric muscular endurance of the anterior trunk (abdominal) muscles, which work with the back extensors to stabilize the spine. It complements the back extension test.

Set-up and execution:

1. Demonstrate the position: forearms on the mat with elbows under the shoulders, legs extended, and the body in a straight line from head to heels. The client supports the body on the forearms and feet.
2. On "go", the client lifts the pelvis off the floor. Timing starts when the pelvis leaves the floor.
3. Coach the client to keep breathing and to hold the straight line. Use the end-point rules in the CSEP-PATH manual: the test stops when the client can no longer keep the straight-line position (the hips sag or pike and are not corrected) or chooses to stop.
4. Record the time in seconds.

Interpretation: the CSEP-PATH client information sheet records the plank as a percentile for age and sex, not as a Health Benefit Rating.

Strengths: no equipment, quick, and directly relevant to core stabilization. Weaknesses:

• The end point needs judgement, so different testers may stop the test at different times.
• Shoulder or low-back pain limits use.
• Motivation strongly affects the result.

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Y Balance Test (Dynamic Single-Leg Balance)

What it measures: dynamic balance and neuromuscular control while standing on one leg and reaching as far as possible with the other foot in three directions: anterior, posteromedial and posterolateral. It complements the static one-leg stance test.

Equipment and preparation:

• A Y Balance kit (centre platform and three reach indicators) or a taped "Y" on the floor.
• Measure each client's lower-limb length (commonly from the anterior superior iliac spine to the distal medial malleolus, with the client supine). This lets results be normalized.

Execution (standard protocol):

1. The client stands on one foot on the centre platform, shoeless, with hands on the hips.
2. Using the free foot, they push the reach indicator as far as possible in one direction, then return to the start position without touching down.
3. Practice trials are followed by recorded trials in each direction for each leg. Follow the order on the CSEP-PATH worksheet.
4. A trial is repeated if the client touches down, kicks the indicator, rests the reaching foot on top of it, lifts the stance heel, loses balance, or takes the hands off the hips.

Scoring:

$\text{Composite score (\%)} = \frac{\text{Anterior} + \text{Posteromedial} + \text{Posterolateral}}{3 \times \text{Limb length}} \times 100$

Compare right with left. Large side-to-side differences, especially in the anterior reach, point to an imbalance worth addressing in training.

Worked example: limb length 90 cm; best reaches anterior 64 cm, posteromedial 98 cm, posterolateral 94 cm.

• Sum $= 256$ cm.
• Composite $= 256 / (3 \times 90) \times 100 = 256 / 270 \times 100 = 94.8\%$.

Strengths: inexpensive, quick, and sensitive to side-to-side differences. Weaknesses: needs practice trials and close attention to faults; results depend on hip and ankle mobility as well as balance.

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Predicted 1-RM

Why predict? The CSEP-CPT Scope of Practice states that a CSEP-CPT is not sanctioned to assess strength with maximal 1-RM protocols, or to design programs based on loads exceeding 90% of the predicted 1-RM. The exception is the CSEP High Performance Specialization, for apparently healthy clients. CSEP-PATH therefore estimates 1-RM from a submaximal effort.

General procedure (follow the CSEP-PATH worksheet for the exact steps):

1. Choose an exercise the client can perform with sound technique, such as a machine chest press or leg press, and adjust the equipment to fit.
2. Warm up with light sets.
3. Select a load the client can lift with good form for a moderate number of repetitions. Predictions are most accurate at 10 repetitions or fewer.
4. The client performs repetitions to fatigue or to technique breakdown, breathing out on exertion. Count only correct repetitions.
5. Estimate 1-RM from the load and repetitions using the CSEP-PATH prediction method. Published equations such as Brzycki and Epley (Section 8.1) work on the same principle.
6. Set training loads as percentages of the predicted value, never above 90%.

Worked example (Brzycki): a client completes 8 repetitions with 50 kg on a machine chest press.

• Predicted 1-RM $= 50 / (1.0278 - 0.0278 \times 8) = 50 / 0.8054 = 62.1$ kg.
• A load of 70% for hypertrophy is about 43.5 kg.
• The CSEP-CPT ceiling (90%) is about 55.9 kg.

Predicted vs. Actual 1-RM (Competency 4.18)